A HISTORY OF CHEMISTRY
A
HISTORY OF CHEMISTRY
FROM EARLIEST TIMES TO THE PRESENT DAY
BEING ALSO
AN INTRODUCTION TO THE STUDY OF THE
SCIENCE
BY
ERNST VON MEYER, PH.D.
PROFESSOR OF CHEMISTRY IN THE TECHNICAL HIGH SCHOOL, DRESDEN
TRANSLATED WITH THE AUTHOR'S SANCTION
BY
GEORGE McGOWAN, PH.D.
THIRD ENGLISH EDITION, TRANSLATED FROM THE THIRD
GERMAN EDITION, WITH VARIOUS ADDITIONS
AND ALTERATIONS
MACMILLAN AND CO., LIMITED
NEW YORK: THE MACMILLAN COMPANY I9O6
The Right of Translation and Reproduction is Rcsei-oett
306
RICHARD CLAY AND SONS, LIMITED,
BREAD STREET HILL, B.C., AND
BUNGAY, SUFFOLK.
First Edition 1891. Second Edition 1898. Third Edition 1906.
PREFACE TO THE FIRST GERMAN EDITION
NEARLY five decades have passed by since Hermann Kopp's classical Geachichte der Chemie l began to appear, and it is now fifteen years since this was followed by the same indefatigable author's JSntwiokelung der Chemie in der neueren Zeit*
The publication of these comprehensive works, in con- junction with which Hofer's Histoire de la Chimie must be named, and the further descriptions of the growth of chemistry within particular periods given both by Kopp himself and by other writers, might lead one to suppose that there was no pressing need for further work in the same direction at the present time.
This point can, the author thinks, be best discussed by his making a few remarks here with respect to the aim and plan of the present volume.
In this History of Chemistry the attempt has been made to describe within short compass the development of chemical knowledge, and especially of the general doctrines of chemistry which have thus been gradually evolved, from their earliest beginnings up to the present day. After a
1 " History of Chemistry."
2 " The Development of Chemistry in Recent Times."
•vi PREFACE TO THE FIRST GERMAN EDITION"
general account of the main directions followed by chemistry in the various ages, the growth of particular branches of the science has been more or less minutely detailed.
In the general descriptions great emphasis has been laid .upon the genesis of particular ideas, and their expansion into important dogmas or comprehensive theories. At the same time, in order that a vivid picture of the various periods aad their distinguishing characteristics might be presented to the reader, short accounts have been given of the works, and in some cases of the lives, of the men who originated and developed such views.
In the special sections, on the other hand, the attempt has been made to collect together fundamental facts, which have been sifted and relegated to their proper branch of the .science, and thus to offer as clear a description as possible of the state of chemical knowledge at the time in question.
That neither in this nor in the history of the develop- ment of theoretical views could completeness be thus Achieved, hardly requires to be stated. But the author has .at all events endeavoured to give a fair synopsis of the most important theories and facts which constitute the foundation of chemistry as we now know it.
The growth of chemical knowledge during recent times, .since Boyle, and especially since Lavoisier, naturally forms the principal subject of the following chapters. The author is fully aware of the many difficulties which have to be met here, difficulties which increase in extent the nearer we approach to the history of our own period. We stand too close to the development of the theoretical views of these latter days to feel certain of always preserving the unbiassed temperament which is essential to the true historian. But,
PREFACE TO THE FIRST GERMAN EDITION vii
notwithstanding this, the author has ventured the attempt to carry the record of the history of chemistry up to the present day.
In this task he has done his best to preserve throughout an objective attitude; and he has further been guided by the earnest desire to contribute effectively towards shedding a clear light upon the opposing views held with respect to the development and the importance of the chemical doctrines of to-day. It has also been his duty as an historian to endeavour to apply to the services rendered by eminent investigators of quite recent years a calmer and juster criticism than has hitherto in many cases been meted out- to them.
ERNST VON MEYER.
LHIP/JO, 7«/t October, 1888.
TEANSLATOE'S PEEFACE TO THE FIEST ENGLISH EDITION
THE author, in his preface to the original German edition, discusses the question whether there is any necessity for a new history of chemistry in his own language at the present day. That there is full room for one in this country will be admitted upon all hands. It is therefore hoped that the appended history will prove not only useful to the student, but also interesting to the general reader who is desirous of gaining some idea of the development of chemical science.
The translator has done his best to reproduce clearly the sense of the German original. And since Professor von Meyer has been so kind as to read over the first corrected proofs, as well as to answer a great many queries, it is hoped that this has been achieved.
A considerable number of small alterations and additions have been made for this edition, inost of them by the author, but some by the translator with the author's concurrence. White these may reasonably be supposed to have improved the book, they have not altered its character in the slightest degree. The translator has further added a number of duplicate references to English journals (to such papers as were published both in German and English), and also a few new ones, for the greater convenience of English readers.
TRANSLATOR'S PREFACE
In conclusion, he would express his indebtedness to the various gentlemen who have been kind enough to give him the benefit of their criticism and advice upon different points, with regard to which his own special knowledge was insuffi- •cient, and also to those others who have assisted him in the matter of references, etc.
UNIVERSITY COLLEGE OF N. WALES, BANG OR, J/orcA, 1891.
AUTHOR'S NOTE TO THE FIRST ENGLISH EDITION
It was a great satisfaction to me that the translation oi this history was undertaken by my former pupil, Dr. McGowan, and I desire to express here my appreciation of the manner in which he has entered into the spirit of the work, and to offer him my hearty thanks for all his trouble in the matter.
May the book find many friends among the English- speaking peoples, and help to stimulate the interest of its readers in the development of our science.
ERNST VON MEYER.
LEIPZIG, February, 1891.
TEANSLATOE'S PEEFACE TO THE SECOND ENGLISH EDITION
THE present edition is a translation of the second German edition (published in 1895), with a number of further addi- tions and alterations, most of these latter having been made by the author, but a good many of them by myself, with his approval; and, as in the case of the previous edition, the proof sheets had the benefit of the author's revision after my own corrections were made.
In his preface to the second German edition Professor von Meyer expresses his gratification at the success of the English version, and then goes on to speak of the .additional sources of information on subjects of historical chemistry which have during the last few years become available for reference. Among these are the Berzelius- Liebig and the Liebig-Wohler Letters, the Letters and Journals of Scheele, Priestley's Letters, and the autobio- graphical fragment which Liebig left behind him. In addition, there are the recently published and valuable his- torical researches of Berthelot on the chemistry of the early Middle Ages, and the writings of Ladenburg, Schorlemmer, Thorpe, Grimaux and others on the development of chem- istry within certain definite periods, or on the life and work •of particular chemists.
xii TRANSLATOR'S PREFACE
I may, perhaps, be permitted to add my word of appre ation to what the author has said with regard to the frieni reception of the first English edition both in this coun and in America, and to express the hope that the presc edition may be found at least equally acceptable.
GEORGE McGOWAN. EALING, LONDON, W. July, 1898.
AUTHOE'S PKEFACE TO THE GEKMAN EDITION
A FEW -words may be prefaced to the third edition of this History of Ghemistry. There are many signs that among the rising generation there is an increase of the historical sense with regard to chemistry and to science generally— a better understanding of the reasons for their existence and growth. This has shown itself in the' publication of a number of valuable historical works in the interval which has elapsed since 1894, the year in which the second edition of this book appeared. The monographs on the history of chemistry, edited by Kahlbaum, have brought to light much treasure in the shape of biographies, letters, etc. ; while a journal, whose aim is the study of the history of the natural sciences and of medicine, was started three years ago and, thanks to Kahlbaum's zealous co-operation, stands chemistry in good stead.
That this historical sense has also been growing in other countries is evidenced — to give only a few instances — by the publication of Berthelot's works on the early history- of chemistry, of Thorpe's historical essays, and of Guareschi's monographs.
Wilhelm Ostwald, indefatigable as a pioneer in the field of physical chemistry, has never tired of laying stress on the
xiv AUTHOR'S PBBFAOB TO THE THIRD (JKRMAN KWTION
iinportanco of historical studios for the understanding of general chemistry ; according to him " there is no more effective means of vivifying and deepening the study of a science than to saturate one's-aolf in ita history." Tho frequent courses of lectures on thu history of chemistry which are given in our (German) universities and collegia arc further evidence of the interest now taken in the evolution of the science.
Besides the works already mentioned, ninny others have been made use of in the preparation of this edition — more especially the continuously augmenting literature of experi- mental research. How much that wa» new and pioneering has thus had to be included ! It required no close examina- tion of the preceding edition to aeo that aomo of the sections of the latter required to bo recast to a connidorable extent, In all the chapters which deal with the chi'mistry of recent times, new matter has either been added or old matter altered with a view to its improvement. In this connection I would wish to express my heartiest thanks to varioua colleagues for the valuable help that they have given mo, Dr. Strunz, with his intimate knowledge of Paracelsus, has suggested several alterations which unable us to form a tinier estimate of this hitherto much-abused investigator, My colleague, Prof. Fr, Foeratwr, has, by his advice and valuable suggestions, helped me materially with the final proofs of the section upon physical chemistry.
May the book in its new form again make itself friend* and help to arouse and strengthen the interest in the historj of our noble science,
ERNST VON MEYER.
1th QrtoliKr, 1!HI4.
TRANSLATOR'S PREFACE TO THE T3 ENGLISH EDITION
THE present edition is a translation of the third Germain edition, published in the early part of 1905, but it contains, at the same time some alterations and additions, made with the sanction of the author; and, as in the case of the- two previous English editions, the proof sheets have had the benefit of the author's revision.
Sir William Ramsay has been kind enough to look through most of the second half of the book, and has suggested a. number of alterations and additions which have materially improved the text. I should also like to take the oppor- tunity-of thanking Miss H. M. E. Aitken for the care which she has taken over the indexes, most of which have been done by her. I have also been much helped by different members of my own family in the reading of proof sheets.
GEORGE McGOWAN.
BALING, LOKDON, W. September, 1908.
I TABLE OF CONTENTS
LIST OF ABBREVIATIONS INTRODUCTION
CHAPTER I
FROM THE EARLIEST TIMES TO THE BIETH os1 ALOHBMT . . 6
Theoretical Views upon the Composition of Substances and especially upon the Elements, 7. Aristotle's Elements, 9.
The Empirical Chemical Knowledge of the Ancients, 10. Metallurgy of the Older Nations— Gold, 13 j Silver, Copper, 14 ; Iron, Lead, Tin, &o., 15; Mercury, 16. The Manufacture of Glass, 17. Pottery, 18. The Manufacture of Soap, 18. Dye- ing, 19. The Beginnings of Pharmacy, 20.
CHAPTER II
THE AGE OB- ALCHEMY 23
General History of Alchemy 25
Origin and First Signs of Akhemistic Efforts, 25. The Alex- andrian Academy, 29. The Alchemy of the Arabians — Geber and his Disciples, 30-32. Alchemy among the Western Nations, 32. Albertus Magnus, Roger Bacon, 34. Arnaldus Villanovanus, 35. Eaymundus Lullus, 36. Pseudo-Basilius Valentiims, 38.
Special History of Alchemy 40
Theories and Problems of the Alchemistic Period, 410. The pseudo-Geber, 41-43. Viewp of Pseudo-Basilius Valentinus, &o., 44. The Philosopher's ' ione, 45.
Practical-Chemical Kna edge of the Alchemists, 48.
Technical Chemistry— j ild, 49. Silver, 49. Copper and other metals, 50. Potted . Glass, Dyeing, 50-51, Pharma- ceutical Chemistry, 51. ; ' '
CONTENTS
Knowledge of the Akhemists with regard to Ohemical Com- pounds, 62. Alkalies, 63. Acids, 64. Salts, 56. Preparations of Antimony, &o., 67. Organic Compounds, 60.
The Fortunes of Alchemy during the last Fowr Centuries, 61.
A Short Review of Alchemistic Efforts, 67.
CHAPTER III
PAGE
HlSTOET OF THE lAIRO-OHEMIOAIi PEBIOD 69
General History of this Period 71
Paracelsus and his School, 71. The latro-Ohemical Doctrines of Paracelsus, 74. Turquet de Mayerne, 78. Libavius, 79. Van Helmont and his Contemporaries, 80. The work of van Helmont, 80-85. Sala and Seniiert, 85. Sylvius and Tachenius, 86. Oeorgiua Agricola, 89. Palissy, 90. Glauber, 91.
Special History of the latro-Chemical Period 93
Technical Chemistry, 93. Metallurgy, 93. Pottery and Glass Manufacture, 96. Dyeing, &o., 95.
Development of Pharmacy and of the Knowledge of Chemical Preparations, 97. Inorganic Compounds, 97. Organic Com- pounds, 102.
CHAPTER IV
HISTORY OP THE PEBIOD OF THE PHLOGISTON THEORY, PBOBI
BOYLE TO LA.VOISIEB 106
INTRODUCTION IQ&
General History of the Phlogistic Period .... 109 Robert Boyle, 109. Mayow, 113. Lemery and Homberg,
114. Kunkel and Beoher, 116. Stahl and the Phlogiston Theory,
117. Pr. Hoffmann and Boerhave, 119.
The Development of Chemistry, and particularly of the
Phlogiston Theory, after State's Time, 122. Neumann, Eller,
Pott, Marggraf, 122-123. Geoffiroy, Duhamel de Mouceau,
Rouelle, Macquer, 123-126. Black, 126. Cavendish, 128.
Priestley, 129. Bergman and Soheele, 131-132.
Special History of the Phlogistic Period 135
Pneumatic Chemistry and its Relations to the Doctrine of Phlogiston, 136. The Discovery of Oxygen and the Composition of Air, 137.
Development of Theoretical Views in the Phlogistic Period 141 Views regarding Elements and Ohemical Compounds, 141. '
CONTENTS
Views regarding Chemical Affinity and its Causes, 144, Geoffrey's Tables of Affinity, 146.
Practical Chemical Knowledge in the Phlogistic Age, 147. The Development of Analytical Chemistry, 148. Boyle, 148. Fr. Hoffmann, Marggraf, Soheele, 149-150. Bergman, 160. The Beginnings of Gas Analysis, 152.
Technical Chemistry in the Phlogistic Age — Metallurgy, 153, The Ceramic Industry, Dyeing, 154.
Teohnico-ohemical Preparations— Acids and Alkalies, 156. The Discovery of Elements, 166. Inorganic and Organic Com- pounds, 158-159.
Pharmaceutical Chemistry, 161.
Concluding Remarks upon t-Ma Period, 163.
CHAPTER V
PAQW
HISTORY OP THE MOST RBOENT PERIOD (PEOM THE TIME OF
LAVOISIEB, UP TO NOW) 165-
Introduction 165
General History of Chemistry during this Period . . . 167
Lavoisier and the Antiphlogistic Chemistry, 167. Lavoisier's Life and Work, 167 et seg. His Combustion Theory, 171-174. Triumph of the Antiphlogistic Chemistry, 175. Beginnings of a Rational Chemical Nomenclature, 178. Guyton de Morveau, 180. Berthollet, 181. Fouroroy, 182. Vauquelin, 184.
The State of Chemistry in Germany at the End of the Eighteenth Century, 185. Klaproth, 186. The State of Chemistry in England, Scotland and Sweden, 188.
Development of the Doctrine of Chemical Proportions, 189. Richter, 190. His Law of Neutralisation, 191. The Beginnings of Stoohiometry, 193. Proust, 193. His Contest with Berthollet, 194. Recognition of Constant Combining Proportions, 196.
Dalton's Atomic Theory 196.
Law of Multiple Proportions, 197-198. Dalton's Attempts to determine the relative Atomic Weights of the Elements, 199. His Atomic Weights and Chemical Symbols, 201-202.
Further Development of the Atomic Theory, 202. Thomas Thomson, 203. Wollaston, 203. Humphry Davy, his Life and most important Work, 204-208. Gay-Lussao, 208. Hie Law of Volumes and Work generally, 208-210. Prout's Hypothesis and its Effects, 210.
Berzelius — A Survey of his Work 212
Biographical Notice, 212-213. His Influence upon the Development of Analytical and Organic Chemistry, 214-216.
b 2
CONTENTS
His Experimental Researches, 214-216. Berzelius as a Teacher and Writer, 216-218. His General Character, 219. Development of the Atomic Theory by Berzelius, 220. His Determinations of Relative Atomic Weights, 221 et aeq. His Oxygen Law, 222.
Influence of Gay-Luseac's Law of Volumes upon the, Atomic Theory, 223. Avogadro's Hypothesis, 226. Application of the Law of Volumes by Berzelius, 226. The Position of the Atomic Theory in 1818, 227. Dulong and Petit'a Law, 230. Influence of the Doctrine of Isomorphism wpon the Atomic Theory, 231. Mitsoherlioh, 231-232.
The Atomic Weight System, of Berzeliua from 1821 to 1826, 233. Dumas' Attempt to alter the Atomic Weights, 235. Failure of this Attempt, 237. Faraday, 237. His Law of Definite Electrolytic Action, 238.
The Mectro-Ohemical Theories of Davy and Berzeliiia, 239 et seq. The Duolistic System of Berzeliua, 243. His Chemical Nomenclature and Notation, 244-247.
Manifestations against Dualism, 247. Discovery of the
Alkali Metals, 248. Recognition of the Elementary Nature of
1 Chlorine, 260. Theory of the Hydrogen Acids (Davy and Dulong),
251. Doctrine of the Polybasic Acids (Liebig), 263. Graham, 234.
Development of the Dualiatic Doctrine in the Domain of
Organic Chemistry, 266. The Growth of Organic Cliemiatry
previous to 1811, 256, The Position of Berzelius with regard to
Organic Chemistry, 267. Development of Views respecting
Radicals, 269.
Isomerism and its Influence on the Development of Organic Chemistry, 260. Observations of Liebig, Wo'hler, Faraday and Berzelius, 261. Clearer Definition of the terms Isomenem, Polymerism and Metamerism by Berzelins, 262.
The older Radical Theory, 263. The Etherin Theory (Dumas and Boullay), 263-264. Liebig and Wahler's Work upon Benzoyl Compounds, 264. The Ethyl Theory of Bending and Liebig, 266, Position of the Radical Theory in 1837, 268. Definition of the term Radical, 269. Bunsen, 270. His Work upon the Oacodyl Compounds, . 271. The Significance of the •Radical Theory, 271.
Liebig, Wdhler and Dumaa—A Survey of their more •important Work, 272. Justus Liebig, his Life and Work, 272. Liebig as a Teacher, 275. His Literary Activity, 277. His experimental Researches, 278. Friedrich Wohler, 281. Wohler as a Teacher and Writer, 281-282. Hia Services to Science, 282-283. Dumas, his Life and Work, 283-286.
The Development of Unitary Views in Organic Chemistry, 286. Substitution Theories, 286. Dumas' Laws of Substitution, 287.
CONTENTS
Laurenfs Substitution or Nucleus Theory, 289. Criticism of the same, 290. Dumas' Type Theory, 291. His Unitary System, 292. The Overthrow of JBerzelius' Dualistic Doctrine, 293. Berzelius' Eight against the Substitution Theory and his: Defeat, 293 et seq.
Fusion of tlie older Theory of Types with the Radical Theory by Laurent and Gerhardt, 297. Laurent and Gerhardt, a Sketch- of their Lives, 287. Gerhardt's Theory of Residues, 298. His. Law of Basicity, 300. Qerhardfsfirst Classification of Organic- Compounds, 300. Hts Reform of the Atomic Weight System, 301. The distinguishing between the terms Molecule, Atom and1 Equivalent by Laurent and Gerhardt, 304. Work preparatory to the new Type Theory— Wurtz and A. W. Hofmann, 306-309". Williamson's Experiments on the Formation of Ethers, 309-310. His Opinions with regard to the "Typical" View, 310. Gerhardt's new Theory of Types, 312. Work preparatory to this, 312. Derivation of Organic Compounds from Types, 314. Gerhardt's Views upon Chemical Constitution, 315. Criticisms upon his Type Theory, 317. Extension of the Type Theory by Kehile, 318. Kekule, 319. Mixed Types, 320, Marsh Gas as a Type, 321, Position of the Type Theory in 1858, 321.
Development of the Newer Radical Theory by Kolbe — A Survey of Kolbe's Ltfe and Work, 322. The He-animation oj the Radical Theory by him, — FranUand's Co-operation, 324. Copulated or Conjugate Compounds, 326. Setting aside of the Notion of Copulation by Frankland, 328. Kolbe'a Carbonic Acid Theory, 828. The Derivation of Organic Compounds from Inorganic, 329. Kolbe's most important Experimental Researches, 330-331. His Attitude towards the older and the newer Chemistry, 332. Kolbe's real Types, 333.
PAOT
The Founding of the Doctrine of the Saturation-Capacity
of the Elements by Frankland 334
Preparatory steps towards this Doctrine, 334. Frankland's Services here, 334 et seq. Assumption of a varying Saturation* Capacity, 337. Discussions on the Subject by Odling, William- son and Wurtz, 338-339,
The Recognition of the Valency of Carbon, 339. Kekule's Services here, 340. Kolbe and Frankland's Share in the Matter, 341.
Development of Chemistry under the Influence of the
Doctrine of Valency during the last Forty-five Years . 34$
beginnings of the Structure Theory — Keku26 and Couper, 344. Establishment of the true Atomic Weights by Cannizzaro, 347.
ixii CONTENTS
Discussions regarding the Nature of " Structure" by Butlerow and Erlenmeyer, 348.
Controversies respecting constant and varying Valency of the Elements, 349. Views upon varying Valency held by IVankland, Kolbe, &o., 349-360; by Erlenmeyer, Wurtz and Naquet, 350. Kekule'a Theory of a Constant Valency, 350 ; Grounds for the Assumption of a varying Valency, 361 et seq.
The further Development of the Structure TJieory—The chief Directions taken by Organic Chemistry during the last forty Tears, 366. Views upon the Linking of Atoms, 355. Constitu- tion of Organic Compounds according to the Structure Theory 1 357. •Saturated and Unaaturated Compounds, 357. SeJculfs Theory of the Aromatic Compounds, 359. Modifications in this Theory proposed by Ladenburg, Glaus and Bwyer, 361-362. Constitu- tion of Pyridine, Pyrrol, &o., 363-364. Victor Meyer's more precise conception of the term Aromatic Com/pounds, 364. Ap- plication of Structural-cJiemical Conceptions to the Investigation of Isomerism, 364. Position-isomerism, 366. Tautomerism or Desmotropism, 367-368. Geometrical Isomerism (Wialicenus), 370. Allo-iBoraeriflm (Michael), 370. The supposed Spaoial Arrangement of Atoms, 370 et seq. Pasteur, 371. The De- velopment of Important Methods for investigating the Constitution of Organic Compounds, 375. Synthetic Methods (Wohler, Kolbe, Frankland, Baeyer, Kekul6, Ladenburg, Fittig, W. H. Parkin, een,, and others), 375. Chemical Behaviour of Organic Com- pounds, 379.
The Main Currents in Inorganic aiid General OJiemistry during the last forty Tears, .381. Application of the Structure Theory to Inorganic Compounds, 382. Important Researches in Inorganic Chemistry, 384. The Discovery of Argon and the other Inert Gases of the Atmosphere, 384. Stas, 386. The Periodic System of the Elements (Newlands, L. Meyer, Mendeleeff), 386. Crookes* Hypothesis of a Primary Material, 390. General Significance of Physico-chemical Investigations, 391. H. Kopp, 391. Ostwald, 393. Van 't Hoff, 393. Willard Gibbs, 394.
CHAPTER VI
.SPECIAL HISTOBY OP THE VARIOUS BBANOHES os1 CHBMISTBY
PBOM LAVOISIER TO THE PBESBNT DAY . . . .396
Introduction 3917
History of Analytical Chemistry 40Q
Qualitative Analysis of Inorganic Substances, 400. Use of the Spectroscope for this purpose, 402. Quantitative Analysis of Inorganic Substances, 402. Klaproth, Vauquelin, 402-403.
CONTENTS mil
Lavoisier, Proust, Berzelius, 403-404. Dumas, Erdmann and Marchand, Marignao, Stas, 404. H. Rose, Wohler, Fresenius, 405. Docimaoy, 406. Volumetric Analysis, 407. Its Development by Gay-Lussac, Bunsen, Mohr, &o., 407. Development of Methods of Gas Analysis, 409. The Analysis of Organic Substances {Lavoisier, G-ay-Lussao and Thenard, Berzelius, Liebig, &c.), 410-414. Legal-ohemical Analysis, 414. . Teohnioo-ohemioal Methods, 415.
PAOB
The Progress in Pure Chemistry from Lavoisier to the
Present Time 417
Special History of Inorganic Chemistry . . . . . 418
The Discovery of Elements and the Determination of their Atomic Weights, 418. Oxygen, Nitrogen and Hydrogen, 419-420. The Halogens, 420. Selenium, Tellurium, &c., 421. Boron and Carbon, 422. Allotropy, 423. The Metals of the Alkalies and Alkaline Earths, 426-427. Beryllium, Cadmium, Thallium, Aluminium, Indium, Gallium, 427-428. Metals of the Cerium Group, 429. Niokel and Cobalt, 430. Chromium, Titanium, Germanium, &o., 430-432. Vanadium and allied Elements, 432. Metals of the Platinum Group, 433. Argon, Neon, Helium, Krypton and Xenon, 434-437. Bayleigh, 435. Ramsay, 435. Supposed new Elements, 437.
Inorganic Compounds, 438. Hydrogen Compounds of the Halogens, 439, Oxygen Compounds of Hydrogen and of the Halogens, 439. Sidphur, Selenium and Tellurium Compounds, 441. Compounds of Nitrogen, Phosphorus, &o., 442-446. Compounds of Boron, Silicon and Carbon, 446. Compounds of the Alkali and Alkaline Earth Metals, 448. Compounds of the Metals of the Iron Group, &o., 449. Compounds of Tin, Vana- dium, &o., 452. Compounds of Gold, Platinum, &o., 453.
Special History of Organic Chemistry in the Nineteenth
Century . 455
Hydrocarbons and their Derivatives, 456. The Alcohols and analogous Compounds, 461. Carboaylic Acids, 465. Acid Chlorides, Anhydrides and Amides, 469. Oxy- and Amido- Acidn, 471. Aldehydes, 474. Ketonea and Ketonic Acids, 477. Carbohydrates and Ghicosides, 480. Haloid Derivatives of the Hydrocarbons, t&c., 483. Nitro- and Nitroso-Compounds, 487. Sulphur Compounds, 489. Organic Nitrogen Compounds (Amines, etc.), 491. Phosphines, Arsines, Stibines, 496. Azo- Compounds, 496. Diazo-Compounda, 497. Hydrazines, Cyano- gen Compounds, 499-506. Pyridine and Quinoline Bases, 606. Their Relation to Vegetable Alkaloids, 510. Pyrrol and analo- gous Compounds, 512. Organo-metattic Compounds, 514.
CONTENTS
PAGE
History of Physical Chemistry in Recent Times . . . 617
Determination of Vapour Density and the Application of this, 519. Dissociation, 521. The Liquefaction of Gases, 522. The Kinetic Theory of Oases, 624. Spectrum Analysis, 524. Atomic Volumes of Solids and Liquids, 628. Laws regulating the Soiling Temperature, 527. Specific Heat of Solid Bodies', 528. Optical Behaviour of Solids and Liquids (Refraction, Circular Polarisation), 520. Diffusion, die., 532. Theory of Solution; Electrolytic Diaaociatimi, 634. The Electrolysis of Liquid or of dissolved Substances, 536. Isomorphism, <&c., 539. Thermo-Ghemiatry,o4l. Julius Thomson ; Berthelot, 642. Photo- Chemistry, 644. Radio-activity, 546. M. et Mme. Curie, 547.
Development of the Doctrine of Affinity since the Time of Bergman, 547. Bergman's Doctrine of Affinity, 548. Berthottet's Doctrine of Affinity, 549. The Supplanting ofBerthollet's Opinions by other Doctrines, 550. The Hevival of Berthollet's Doctrines, 663. The latest Development of the Doctrine of Affinity, 653.
Sketch of the History of Mineralogical Chemistry during
the last Hundred Tears 659
Its Earlier History, 559. The Chemical Mineral System of Berzeliua, 561. Other Mineral Systems, 562. The more recent Development of Mineral Chemistry, 562-563. The Artificial Production of Minerals— Beginnings of Geological Chemistry, 664.
Development of Agricultural and of Physiological Chemistry , 569
Agricultural Chemistry and Vegetable Physiology, 570. The Humus Theory, 570. Reform of Agricultural Chemistry by Liebig, 671. Its further Development by Liebig and his School, 572. Nitrification and the Assimilation of Free Nitrogen by Plants, 674-576.
The Development of Phyto-Chemistry, 676. Important Phyto-chemioal Researches, 677-579.
The Development of Zoo-Chemistry, 580. Researches upon the Constituents' of the Animal Body, 580. The Chemistry of the Animal Secretions— Saliva, Gastric Juice, Bile, Blood 682-583 ; Milk, Urine, 584. Metabolism, 586. '
Fermentation; Putrefaction, 588. Views regarding Fer- mentation, 588 et seq. Organised and Unorganised Ferments, 590. The Phenomena of Putrefaction, 591. The Ptomaines' 691.
• The Relation of Chemistry to Pathology and Therapeutics, 592. Bacteriology, 593. Antiseptics, Anaesthetics and Anti- pyretics, 593-694.
The Relation of Chemistry to Pharmacy, 595.
CONTENTS
History of Technical Chemistry during the last Hundred
Years 597
Introduction, 597. Development of Technical Instruction, 599. Literature on Technical Chemistry, 600.
The Progress of Metallurgy, 601. Iron and Steel, 601. Nickel, Silver, the Galvano-Plastic Process, Aluminium, &o., 603-605. Mineral Pigments, 605.
Development of the Great Ghemical Industries, 606.
Sulphuric Acid, 607. The Soda Industry, 609. Hydro- chloric Acid, Chlorine and Bleaching Powder, 611-612. Bromine and Iodine, 612. Electro-chemical Industry, 613. Nitric Acid, Gunpowder, 613-616. Other Explosives, Matches, 815-616.
The Manufacture of Soap, &o., 617. Ultramarine, 618. Glass, Earthenware and Pottery, 618-619. Mortar, Paper, <320-62i; Starch, Beet Sugar, 621-622.
Fermentation Proceanes, 623. The Manufacture of Spirits, 624. The Quick Vinegar Process, 624.
The Aniline Ooloura and other similar Dyes, 624. Alizarine, Phthalelns, Azo-Dyes, 626. The Safranines, 628. Indigo Blue, >629. Dyeing and Tanning, 631.
Various Chemical Preparations, 632. Various Proditzts from Coal Tar, 633 et seq. Illuminanta, 637. Heating Materials, 639.
The Growth of Chemical Instruction in the Nineteenth
Century, more especially in Germany .... 642 The State of Education in Science at the end of the Eighteenth Century, 642. Experimental Lectures, 643. The Development of Practical Instruction, (Berzelius, Liebig, &c. ), 1344. The Erection of Laboratories for General Instruction, in Germany, 645. Erdmann, 846. The State of Scientific Education in Prance, Great Britain, &o., 647 ft seq. Improve- ments in the Construction of Chemical Laboratories, 649.
Chemical Literature. 650. Text-books, 650. Larger Treatises and Encyclopedias, 651. Periodical Journals, 652. Yearly Reports (Jahresberichte), 854. The Necessity for Criticism in Chemical Literature, 654. The Study of Original Memoirs, 655.
INDEX OF AUTHORS' NAMES ' • ®&I
INDEX OP STJBJECTS -• ®?^-
ABBREVIATIONS OF THE NAMES OF MOST OF
THE JOURNALS TO WHICH REFERENCE
HAS BEEN MADE
Ann. Ohem. . . Liebig's Annalen der Oheinio und Pharmaoie (began
1832). Ann. Ohim. . . Annales de Ohimie et de Physique (begun 1816 ; five
series).
Ann. de Ohimie . The same journal from 1780 to 1815. Ann. des Mines . Annales dee Mines. Ann. of Philosophy Annals of Philosophy (edited by Thomas Thomson,
1813-26). This journal was subsequently merged
in the Philosophical Magazine.
Ann, Phys. . . . The new Series (Neue Folge) of Poggendorff s Annalen. Archiv Phcurm. . Arohiv der Pharmaoie (begun 1832). Bayer. ATcad. . . Sitzungsberiohte der Bayerisohen Akademie der Wiss-
enschaften. Ber Beriohte der Deutschen chemisohen Gosellsohaf t (begun
1868).
Bull. Soc. Ohim. . Bulletin de la Sooiete Chimique de Paris (begun 1864). Ohem. Centr. . . Ohemisohes Centralblatt (begun 1848). Ohem. News . . . Chemical News (begun 1860). Ohem. Zeitung. . Chemiker Zeitung (published by G. Krause in
Coethen). Oompt. Rend. . . Comptes Bendus des Seances de 1' Acaddmie des SoienceB
(began 1835).
Orell'aAnn. . . . Chemieohe Annalen von L. v. Oell (1784-1805). Dingl. Journ. . . Dingler'a Polytechnisches Journal (begun 1820). Gazz. Ohim. ItaJ. . Gazzetta Ohimioa Italiana (begun 1871). Gilb. Ann. . . . Annalen der Physik von Gilbert und Gren 1798-1824).
rBericht fiber die Entwiokelung der Chemischen Indus-
Hofmann's I trie wtthrend des letzten Jahrzehnts von Hofmann
Bericht, efec. . j (began 1875, bnt oeased after the publication of
«• two volumes). Jahres. Berz. . . Jahresberichte fiber die Fortschritte der Chemie und
Mineralogie von Berzelius (1821-47). Jahres. d. Chemie Jahresberiohte fiber die Fortsohritte der Chemie von
Liebig und anderen (begun 1847).
LIST OF ABBREVIATIONS xxvii
Journ. Ghem. Ind. Journal of the Society of Chemical Industry (began 1882).
Journ. Chem. Soc. Journal of the Chemical Sooiety (Memoirs and Pro- ceedings, vola. i.-iii., 1841-47 ; Journal begun 1848).
Journ. de Phys. . Journal de Physique (1778-94 ; 1798-1823).
Journ. pr. Ghem. . Journal fur praktische Ohemie (begun 1834 ; the new series begun 1870).
Mon. Scient. . . . Moniteur Soientifique (edited by Quesneville, begun 1857).
Phil. Mag. . . . Philosophical Magazine (begun 1798).
Phil. Trans. . . . Philosophical Transactions of the Royal Sooiety begun 1666).
PM. Trans, fl. . . Philosophical Transactions of the Royal Sooiety of Edinburgh (begun 1788).
Pogg. Ann. . . . AnnalenderPhysikundChemie von Poggendorff (begun 1824 ; new series begun 1877).
Proc. £. S. ... Proceedings of the Royal Sooiety [begun 1800. Vola . i.-iv. (1800-1843) are entitled "Abstracts of the Papers printed in the Philosophical Transactions of the Royal Society of London," and vols. v., vi. (1843-1854) "Abstracts of Papers communicated to the Royal Society." The final form of title, "Proceedings of the Royal Society of London,"1 begins with voL vii., published in 1856],
Proc. JR. 8. E. . , Proceedings of the Royal Sooiety of Edinburgh (begun 1845).
Rec. Tram. Chim. . Recueil des Travaux Ohimiques (begun 1882).
Schweigg. Jowrn. . Journal filr Ohemie und Physik von Schweigger (1811-33).
Wagner* s Jahresber. Jahresberioht liber die Leistungen der chemisohen Technologic von Wagner (begun 1856).
Wi&n&r Monatehqfte Monatshefte fur Chemie undverwandte Theile anderer Wissenschaften (begun 1880).
ZtacJvr. anal. Chem. Zeitsohriftfuranalytisohe Chemie von Fresenius (begun
1862). fZeitschrift fur angewandte Ohemie (this journal was
Ztufar. ang&to. I stftrted in 1887 M the Zeitschrtft filr Chemiache Chem. . . . { Industrie, but its title was changed in 1888).
Ztachr. onorgon i „ . , , ... ... . , _,
~f, J-Zeitsohrift fur anorgamsone Ohemie.
Ztachr. Chem. . . Zeitsohrift for Chemie (1865-71) ; this was a continua- tion of the Kritisohe Zeitsohrift (begun 1858).
Ztechr. phys. Chem. Zeitschrift fUr physikalische Chemie, StSohiornetriev, und Verwandtschaftslehre (edited by Ostwald and van 't Hoff; begun 1887).
A HISTOKY OF CHEMISTRY
INTRODUCTION
CHEMISTRY has for the last two hundred and forty years or so been defined as the study of the composition of substances. Its first task, therefore, lies in ascertaining the constituents of which the material world surrounding us is composed, in1 'reducing these constituents to their elements, and in building up new chemical compounds from the latter. Hand in hand with these analytic and synthetic problems there goes the further task of determining the laws which regulate the chemical combination of matter.
The problems just indicated occupy, in the widest sense of the word, the attention of chemists to-day. The prob- lems of chemistry were, however, different in former times, and it is precisely these differences in aim which characterise the various epochs into which the history of the science may ^therefore be divided.
J~^ \The oldest nations with regard to which we possess /.. -*able information — the Egyptians, Phoenicians, Jews and if" ^"vpg — did indeed possess a certain disjointed knowledge of
°rJ ^cal processes acquired accidentally ; but these were C \ 'd for their practical results alone, and not with the Y%p^f deducing any comprehensive scientific explanation Qj. vjf^m. We meet with similar conditions among the Ailtured European nations, the Greeks and Romans most °^ *ne*r knowledge of chemical facts to the H'^ named- Nowhere do we find in anoiquity the ^ea^\o gain an insight into chemical processes byt
f" \ B
A HISTORY OF CHEMISTRY
INTRO.
means of definitely planned experiments. Although the Andents were wholly without such data, furnished by exac research, as are nowadays held to be indispensable, this did not prevent them from speculating as to the nature of the universe: indeed, those theoretical views upon the nature of matter, on the "elements" of which the world was composed, have given to the earliest age of chemistry its own particular stamp. Some of these systems-ospeci- ally Aristotle's system of the elements-continued ^ to hold away for many centuries, and influenced more especially the who'le teaching of the Middle Ages.
From the above-mentioned doctrine of the nature of the elements was developed the theory of the transmutation of metals, or rather the fixed belief that one element can be transformed into another. Even so far back as the beginning of our own era, at first in Egypt, there began the striving to transmute the base metals into the noble, to " create " gold and silver.
The art by which this was to be achieved was termed chemia (•xrj/j.eCa), a name dating, so far as actual proof goes, from the fourth century, but in reality probably from an earlier period.1
There are many indications that this conception of the aim of chemistry and of the problems which it had to solve- predominated for centuries following, e.g. it lies at the root of the definition given by Suidas,-the author of an encyclopedia, who lived in the eleventh century: "
isfcry, the artificial preparation of silver and gold;" i
" xflvcroTroifa " was a very common designation for chemi^v over a long period of time. /
This task, the solution of which was the aim
1 This word is of Egyptian origin and is probably founded on Egyptian word cham or chSmi, the name for Egypt. It al» however, "black," and hence there IB still some doubt whethe w,°rt' Wiufla of that period denotes Egyptian art or, as Hoffmann i/ ajpfclc^fr "Chemie," in the Dictionary of Chemistry edited by A.^ ^§V endeavours to prove, the employment of a black-coloure£/'ratiojl valuable for alchemistical purposes. The mode of writi'8 the derivation of this word from xv^As, are to be regarded '/
INTBODUOTION
so-called Alchemy,1 characterises the alchemistic period, a period extending from at least the fourth century of our era to the first half of the sixteenth. It is impossible to state with perfect exactitude the date at which alchemy took its rise, its origin being lost in the mists of the past. The labours of the alchemists, who strove by all imaginable methods to attain to the philosopher's stone (by the aid of . which not only were the noble metals to be produced from th'e base, but also the life of man to be prolonged), had the effect of largely extending the area of the then existing knowledge of chemical facts.
In the first half of the sixteenth century, almost contem- poraneously with the Reformation, i.e. with the birth of a new epoch in the world's history, chemistry began to develop in a new direction, without, however, losing all at once its alchemistic tendencies. Chemistry, which had already proved itself a valuable helpmeet to medicine in the preparation of active remedies, came to be looked upon as the basis of the whole medical art. Health and illness were reduced to chemical processes in the human body ; only by means of chemical preparations could an unhealthy body be restored to its normal condition ; in short, the absorption of medicine in chemistry, the fusion of both together, was the cry which emanated from Paracelsus. Van Helmont, de le Boe Sylvius, Tachenius and others were the chief exponents of this doctrine, which characterises the period of Medical or latro-Chemistry. The fact that technical chemistry was advanced at the same time, through the labours of indi- viduals such as Georgius Agricola, was without influence on the prevailing tendeucy of the science of that age.
From the middle of the seventeenth century onwards, the iatro-chemical current gradually underwent substitution by - another. After that date chemistry strove hard to become a self-supporting branch of natural science, quite independent of every other. Indeed, the history of chemistry proper begins with Robert Boyle, who taught, as its main object,
1 This term with the Arabic prefix "al" became naturalised at a very early date.
B 2
4 A HISTORY OF CHEMISTRY INTRO.
the acquisition of a knowledge of the composition of bodies.
The conception of this aim. marks the date from which chemistry may be regarded as a science striving towards an ideal goal along the paths of exact research, without regard to practical results, and solely with the object of arriving at the truth.
By far the most important problem, whose solution occupied all the chemists of note at that day, was the question of the chemical reasons underlying the phenomena of combustion. Since Stahl's attempt to explain the latter, the hypothetical tire stuff Phlogiston — which was supposed to escape during every combustion — was regarded as the universal principle of combustibility. This doctrine held sway over chemists at the end of the seventeenth and during the greater part of the eighteenth centuries to such an extent that we are justified in characterising this period (after the death of latro-chemistry) as the period of the Phlogiston Theory.
The fall of the latter, and its replacement by the anti- phlogistic system of Lavoisier, bring us to the commencement of the chemical era in which we are still living. For, upon the foundation laid by Lavoisier and his co-workers, and firmly fixed by Dalton, Berzelius and others, the structure of the new chemistry rises. The founding and developing of the chemical atomic theory, and its extension to all parts of chemical science, characterise this latest epoch, to which the period of Lavoisier's reform of chemistry was a necessary stepping-stone ; it is, therefore, to be designated as the period of the Chemical Atomic Theory. An insight into the conditions which it involved being only possible by careful quantitative researches, the balance has been, since the time of Lavoisier, the most valuable instrument of the chemist. H. Kopp is, therefore, fully justified in naming the epoch which begins with the French savant the period of quantitative research. Of late years the first aim of chem- istry, i.e., the exact determination of the composition of substances,, has been accompanied by the investigation of
INTRO. INTRODUCTION
the relations which exist between their physical, properties and chemical composition. Physical chemistry, with the accompanying doctrine of affinity, has made immense strides, and has greatly broadened its foundations during the last two decades. But the light of the atomic theory permeates the whole, so that, in spite of many attempts to dispense with it, one is still forced to regard the latter as the guiding star of modern chemistry.
CHAPTER I
FROM THE EARLIEST TIMES TO THE BIRTH OF ALCHEMY
THE characteristics of this period, which have been already referred to, justify one in designating it the period of crude empiricism with regard to chemical facts. In sharp contrast with the disinclination of the Ancients towards experiment, through which alone the secrets of nature are to be un- ravelled, stood their great love of speculation, by means of which they did not hesitate to attempt an explanation of the ultimate reasons of all things. Aristotle, to whom the natural sciences owed the direction which they followed for a very long time, pointed to deduction as the road which should lead to the goal. Instead of drawing general conclusions from accurately observed facts, the Ancients preferred to advance from the general to the particular. The position of all the natural sciences in far-back times, especially that of chemistry, is sufficient to prove how the most mischievous errors crept in and became firmly established in consequence of following the purely deductive method.
The philosophical writings of the Ancients, especially those of the Greeks and Romans, give us a tolerably dis- tinct idea of their theoretical views. Certain writings of Aristotle, e.g. irepl ovpavov and irepl ^evea-eco? Kal fyQtopas, and, also the " irepl \t$a>v " of his pupil Theophrastus, are of especial value for the criticism of the empirical chemical knowledge of these times. The works of Dioscorides on Materia Medica and particular chapters of the Historia Naturalis of the elder Pliny give us an exceptionally clear
CH. I THE ELEMENTS OF ARISTOTLE 7
jnsight into the knowledge of the Ancients. Dioscorides, who was born about the middle of the first century at Anazarbos, enlarged his acquirements, alread}r great, by experiences collected on long journeys. His fame as a physician holds good among the Turkish doctors to this day. The work of Pliny above-mentioned contains exceedingly valuable records of the state of scientific knowledge in his time ; it also shows, however, that the author was by no means master of the immense amount of material which he had collected 1 from tradition, but which he had not really assimilated.
Theoretical Views upon the Composition of Substances, and especially upon the Elements?
The question of the ultimate constituents of bodies, i.e., of the elements which go to build up the world, occupied the minda of the oldest nations. To give an exhaustive description of their speculations on the point does not come within the scope of this work ; what is wanted is rather to call special attention to those views which have exercised a permanent influence upon the chemical ideas of later times.
This applies in a particular degree to the doctrine of the elements, which originated with Empodocles, although it usually bears Aristotle's name ; also, but to a much lesser extent, to the ideas of the older Greek philosophers regarding the original material of which the world, according to them, was built up. Views like that of Thales (in the sixth cen- tury B.C.), that water is the ground material, or those of Anaximenes and Hcraclitus (in the same century), who
1 Pliny the younger characterised the work of his uncle as "opun diffiutwn, eritditum, ii&c. minits varium, quam ipaa natura," and similar admiration of it was expressed by other authors of the day. Our thanks are due to E. 0. von Lippmann, who has recently published a memoir entitled Die chemwcheii' Kenntniaae des Plinim (" Pliny's Knowledge of Chemistry"), in which the whole subject is treated in lucid style fitt'iife ,, Mittheilungen aus dem Osterlande, voL v. p. 370). *•'
2 Of. Kopp, Getichichts der Ohemie, vol. i. p. 29 ; vol. ii. p. 267 ; also Hofer, Histoire de la Chimie, vol. i. p. 72.
8 FROM EARLIEST TIMES TO THE BIRTH OF ALCHEMY o
ascribed to air and fire respective)}7 the same vdlc, have hs no influence upon the development of chemical knowledge.
Democritus (in the fifth century B.C.) also took a grour material as the basis of his speculations, but subdivided th further in that he imagined it to be made up of the smaller possible particles, of atoms, which differed from one anothe in form and size, but not in the nature of their substanci All the changes in the world consisted, according to him, i the separation and recombination of these atoms, which wei supposed to be in a state of continual motion. This doc trine, which at first sight appears to accord with our presen chemical atomic theory, but which in reality has nothing i: common with the latter, was further developed by Epicurus as may be well seen in the didactic poem of Lucretius, D E&nim Nat-ura.
The four so-called "elements" — air, water, earth, an< fire— were regarded by that intellectually great philosophei Empedocles of Agrigent (about 440 B.C.) as. the basis of th< world ; but neither he himself nor Aristotle, who adopted thes< into his system of natural philosophy, looked upon them a< different kinds of matter, but as different properties carriec about by one original matter.1 Their chief qualities (the primus qualities of the later scholastics) he held to be those apparent to the touch, viz., warm, cold, dry, and moist. Each of the four so-called elements is characterised by the pos- session of two of these properties, air being warm and moist, water moist and cold, earth cold and dry, and fire dry and warm. The differences in the material world were, therefore, to be ascribed to the properties inherent in matter. From the assumption that these latter can alter, there necessarily follows the immediate conviction that substances can be transformed, one into the other. It is easy to see how, when based upon speculations of this nature, the belief in the transformation of water into air should establish itself, for both^have the property of moistness in common, while cold, the individual property of water, can be converted by the
' Cf the ingenioua exposition by Tli. (lomperz m his work " Denker," p. 183 (Leipzig, Veit and Co.).
THE ELEMENTS OF ARISTOTLE
addition of heat into the second chief property of air. And it is not surprising that considerations of this kind on the states of aggregation of matter should lead to the idea of transforming one kind of matter into another. It was doubt- less by the generalisation of such views that the belief in the possibility of the transmutation of metals, which formed the chief feature of the alchemistic period, grew to the extent that it did.
Aristotle considered that his four elements were insufficient in themselves to explain the phenomena of nature ; he there- fore assumed a fifth one, termed ovcrta, which he imagined to possess an ethereal or immaterial nature and to permeate the whole world. As the " guinta essentia" this played a great part among the followers of the Aristotelian doctrine in the Middle Ages, and gave rise to endless confusion, from the endeavours of many (who, unlike Aristotle, supposed it to be material) to isolate it.
There seems to be a high degree of probability in the assumption that Empedocles and Aristotle did not themselves deduce their theory of the elements, but derived it from other sources ; thus the oldest writings of India teach that the world consists of the four elements mentioned abovear together with ether,2 which last is most likely related to Aristotle's ova-ia.
It is unnecessary to point out how widely the above views of the Greek philosophers with regard to the elements de- viate from the conceptions of modern chemistry.
With respect also to the meaning of the term " chemical combination," one meets, even if only occasionally, with opinions diametrically opposed to those obtaining at the present day ; the formation of a substance by the interaction of others was looked upon as the creation of a new matter, and the destruction of the original substances from which it was produced was assumed. Everywhere men were contented
1 Instead of air, the element wind is given.
2 So teaches Buddha (as Dr. Pfuiigst has been good enough to inform me) ; see the Aiiffitttara Nikflja, vol. i. fol. ce. Here consciousness is named as the sixth element.
10 FROM EARLIEST TIMES TO THB BIRTH OF ALCHEMY" n
with theoretical explanations, without attempting to prov their correctness by actual experiment. This want show itself very markedly in the manner in which the Ancient regarded "the numerous chemical facts which they had learnei by empirical methods, and probably for the most part b; accident.
The Empirical Chemical Knowledge of the Ancients.1
The Egyptians stand out prominently from among tin earlier civilised nations as having applied their knowledge o chemical processes, acquired by chance observations, to usefu purposes; the needs, of everyday life and the desire to maki that life a comfortable one were the incentives.
Their country formed a kind of focus in which was con centrated the chemical knowledge of the time, if one may sc designate an acquaintance with technical processes. Tht Egyptians already possessed at a very early date a lorgi experience in the production of metals and alloys, in dyeing in the manufacture of glass, and also in the making anc application of pharmaceutical and antiseptic preparations The chemical art proper, revered as " holy " (ayia re^vrf), wnt jealously guarded by the priesthood as a treasure at once precious and profitable. Only the elect might penetrate it.1 mysteries. That laboratories, in which chemical operation of various kinds were carried out, actually formed adjuncts to the temples, is clearly proven by the inscriptions found ir such chambers, e.g. at Dendera and Edfu.
There can scarcely be a doubt that the Phoenicians anc Jews obtained their knowledge of the manufacture of import- ant technical products from the Egyptians. In like manner and to an even greater extent, there was a wealth of chemical experience laid open to the Greeks, and afterwards to the Romans, by reason of their close relations with the ancient country CUmi (see p. 2, note 1). The writings of such
1 Of. Kopp-j Gesch. d. Qkemie, vole. iii. and iv. ; Hcifev, Hint., vol. i. p. 100 et seq.
t EMPIRICAL CHEMICAL KNOWLEDGE OF THE ANCIENTS 11
•eminent Greek philosophers as Solon, Pythagoras, Demo- •critus and Plato, who succeeded in gaining the confidence of the Egyptian priesthood, contributed in no small degree to ttho spread of such practical knowledge.
But all the knowledge so gained was purely empirical ; long aiges were to paas before the various items of which it was •composed were brought together under a general scientific standpoint. In this section of the book merely those por- tions of applied chemistry which were known to the Ancients will be discussed. That a people, so gifted as the Greeks, .should have failed to understand how to group together the numerous observations in those subjects which lay ready to their hand, and to draw conclusions from them, can only be explained by the whole tendency of their thought, and particularly by their overvaluing the deductive and under- valuing the inductive method. Aristotle's opinion that •" industrial work tends to lower the standard of thought " was certainly of influence here. In accordance with this xlictum the educated Greeks held aloof from the observation .and practice of technical chemical processes ; a theoretical .explanation of the reactions involved in these lay outside their circle of interests. To this want of sympathy is cer- tainly to be ascribed the fact that the discovery of even the most important chemical processes is but very seldom to be •connected with the names of distinct historical persons ; while, on the other hand, the old historians give detailed records of those men who advanced untenable opinions on the •constitution of the world.
Before giving an account of the state of practical chemical knowledge in early times, it may be remarked, in passing, that much uncertainty often prevailed in consequence of •different products being called by one and the same name. Substances were not distinguished according to their ^ chemi- cal behaviour, the investigation of which possessed no interest for the Ancients, but were classified according to their out- ward appearance and source, a confounding of similar or identification of dissimilar substances thus frequently result- ing. Two samples of one and the same compound— soda, for
12 FROM EARLIEST TIMES TO THE BIRTH OF ALCHEMY OH.
instance — were looked upon as different, if the external appearance seemed to indicate a dissimilarity. Much dis- crimination has been found to be, and still is, necessary in order to clear up the indistinct points in the records of the old historians.
Metallurgy of the Old Nations.1
We find in the earliest records of the civilised nations (the Egyptians, Jews, Indians, etc.) an acquaintance with the working of different metals. By the younger of those nations mythical personages were held to have taught this art, e.g. Prometheus, Cadmus, etc., by the Greeks. If the translations of the Hebrew words in the Old Testament signifying' '' metals " are correct, then the Jews were acquainted with six, viz. gold, silver, copper, iron, lead and tin ; this may be considered certain as regards the first four, which either occur native or are readily reduced from their ores. They are recorded in the Old Testament in the order just given.
The name " metals " is derived, according to Pliny, from the fact of their never occurring separately but in veins together, /ACT' aXXa.2 Even at that early period, lustre, ductility and hardness were held to be characteristics of a metal. With regard to the origin of metals and ores in the interior of the earth, the Ancients had formed the most extravagant conceptions; they believed, on the ground of Aristotle's weighty testimony, that they were produced by the penetration of air into the vitals of the earth, and con- sequently assumed that the amount of metal or ore increased as the mine proceeded inwards. This view long continued! to be held.
1 The following works have been used for reference :— R. Andree, Die Metalle bei den Naturvdlkern (Veit and Co., Leipzig, 1884) ; Beck, OeschicMe dea Siaena (Vieweg, Braunschweig, 1884; 2nd ed. 1891); A. Rossing,. Geschichte der Metalh (Berlin, 1901) ; 0. Schroder, Sprachveryleichung und Urgtuchichte (Jena, 1883) ; and also various treatises by K. B. Hofmann, to whom the author is greatly indebted for much information on the subject.
'J Herodotus gives fj.4ra\\ov as signifying a mine.
I METALLURGY OP THE OLD NATIONS 13
The Greeks, and especially the Romans, were intimately acquainted with many metallurgical processes ; Dioscorides, Pliny, and later historians give fairly exact data for the ob- taining and smelting of ores, but not the slightest attempt is made to explain the chemical processes which this involves.
The noble metals gold 1 and silver, whose stability in the fire had not escaped the Ancients, were those earliest known (in prehistoric times), and were highly valued ; the fact of their occurring native, and the ease with which they can be worked, afford a sufficient explanation of this.2 The exceed- ing malleability of gold excited the astonishment of the older nations in a high degree, and rendered possible the gilding of objects by covering them with thin plates of the metal. The later discovery of affixing a layer of gold by means of the amalgamation process was known considerably before the time of Pliny.
In the second century B.C. we meet with the first records 8 of a cupellation process, by which gold was freed from admixtures (this process, however, had already been in actual use for centuries) ; in fact, an operation similar to the so- called lead process was then carried out, gold dust being melted with lead and salt for a number of days. The puri- fication of gold by means of mercury was also well known in Pliny's time.
1 Of. the careful study by H. Weiasbuch : — Das Gold im alien Aegypt&n (Dresden, 1901).
3 The gold mines of Nubia (the Egyptian name nub, i.e. gold, is perhaps connected with the designation of that country) were worked very ex- tensively by the Egyptians. According to the records of Agatharchides and of Diodorus Sioulus, in which pity is expressed for the slaves employed in the work, the finely ground gold ore was washed out and the heavy residue melted. In the time of Barneses IL the mines yielded gold to the value of £125,000,000 sterling per annum. The gold-producing land of Ophir, from which the Phoenicians obtained the precious metal, ia supposed to have been in India, Midian (Arabia), or on the east coast of Africa. The same energetic trading nation opened up for the Greeks the first gold mines on the island of Thasos.
8 This recprdj which originated with Agatharchides, is to be found in Diodorus.
14 FROM EARLIEST TIMES TO THE BIRTH OF ALCHEMY en.
Silver, which the enterprising Phoenicians are supposed to have supplied to the other civilised nations from Armenia and Spain, where rich silver ores occur, was, according to the record of Strabo, i.e. at the beginning of our era, purified in a precisely similar manner to gold, viz. by fusion with lead. The separation of silver from gold does not appear to have been known before our era, at any rate an extant record 1 states that Archimedes was not possessed of the means to accomplish this. From indications which Pliny gives, however, it appears that in his time a kind of cemen- tation process was practised, which probably consisted in the treatment of silver containing gold with salt and alum shale. Moreover, an amalgam of gold and silver was regarded in ancient times as a particular individual metal, being termed axm 2 by the Egyptians, and qXetcTpo? by the Greeks (amber being distinguished as TO tf\eKTpov). From this also it may be concluded that at that time no method was known of separating the metals.
The data concerning copper (termed ^a\«o?, aes3), which has been known from time immemorial (being first found in the neolithic stone age), frequently refer to its alloys with other metals, especially to bronze; the latter, as is well known, was very early used for making weapons, ornaments, and utensils. Copper, which was universally employed in prehistoric times, was found native in many places (e.g. in Egypt.X or was readily smelted from malachite or similar copper ores. All the civilised nations, which have been named, were acquainted with bronze before they had learnt to prepare its other constituent, metallic tin, no mention of which is made in old Egyptian records. With regard to the smelting processes by which the " aes " of the Ancients was obtained, nothing certain is known.
1 Archimedes attempted to determine whether the crown of King Hiero
»^ and} V0' how much ; tbis problera he trie* to "
e specifio gravity, not by chemical nieana. The Greek word &ff1)tutv (asem) is derived from this The Roman aes haa the same stem as the Sanscrit word avnj,
"
(so called because of ita occurrence in Cyprus).
r
i METALLURGY 0V THE OLD NATIONS 15
Iron, the extraction and working of which was not dis- covered till after that of copper and bronze, but which, nevertheless, goes back to very ancient times also,1 was pre- pared in smelting furnaces ; the old authors do not, however, give any particulars as to the actual process.2 The ores used are supposed to have been brown iron ore and magne- tite ; that meteoric iron was first employed is an improbable and unproven assumption. The tempering of iron was early learnt in Ancient Egypt ; even in the time of Pliny the un- desirable property of impure iron, which we now term brittle- ness, was known, and its capability of assuming the peculiarity of the magnet stone when brought into contact with the latter was also observed.
Lead 8 was likewise known from very early times, having been prepared and turned to good account by the Greeks and Romans, more especially. Little, however, is known with regard to the smelting processes for it, Pliny's records on the subject being indistinct; but the smelting was probably carried out on a refining hearth. On the other hand, we have many details as to the use of lead for making water pipes, writing tablets, coins, etc. Soldering with lead or with an alloy of lead and tin was also well known. Since cooking utensils were often made of lead, symptoms of lead poisoning occurred frequently; but notwithstanding this, the metal was used as a medicine.
Recent discoveries in Egyptian tombs have brought to- light the fact that tin also was prepared fairly pure in olden times, and that it found numerous applications. Among the Romans lead and tin were distinguished from one another as-
1 According to Lepeiiw, iron lias been in use in Egypt for more than 5000 years, having served primarily for the manufacture of hard instru- ments, while utensils of all kinds were made from bronze.
2 Old Roman smelting furnaces with their appurtenances have recently been excavated near.Eiaenberg in the Pfalz. The form of apparatus used by the Egyptians for the smelting of iron can be arrived at approximately from inscriptions, etc. ; it is worthy of note that bellows of the same- shape as those of Ancient Egypt are in use in the interior of Africa at the- present day.
s Of. K. B. Hofmann's Das Bhi bei den VMkern des Alterthuma (Berlin, 1885).
16 FROM EARLIEST TIMES TO THE BIRTH OF ALCHEMY OH.
plumbum nigrum and plumbum candid-urn.1 The alloy of the two together, i.e. solder, played, as already mentioned, an important part in technical work. Still older, and of even greater significance, was the use of bronze,8 which one meets with among the most ancient civilised nations.
Zinc,3 as an individual metal, was certainly not known to the Ancients, but its alloys with copper (^a\«09, o/je/%aX/co?) found the widest application.
Brass, the first description of which is given by Aristotle as the " metal of the Mosynoeci " (from which the German word Messing, signifying brass, is undoubtedly derived), was for long regarded as copper which had been coloured yellow by fusing it with an earth (cadmia) ; * it was only recognised as an alloy at a much later date. The change in colour produced in copper by certain additions to it played — in the transmutation of metals — an important part in the alchemistic age.
The first .records as to mercury are to be found in Theophrastus (about 300 B.C.), who gives its preparation
1 The word atannum, which -now denotes tin, appears in Pliny's time to have signified an alloy of tin and lead. Whether the /cacrcrfTepoi of the Iliad stood for tin is likewise highly problematical. It is equally un- certain from whence the Phoauicians obtained this metal (or an alloy of it) ; whether from India, with which they had commercial relations, or from Britain and Iberia. The similarity between the Sanscrit word ktmlitu and the Greet word Kcurfftrepos has been used as an argument in favour of the former Assumption (cf. A. v. Humboldt, Koxmou, ii. § 409).
2 K. B. Hofmann considers that the name bronze, with regard to the origin of which there has been muoh dispute, is probably derived from the word Ppovrfiffiov, meaning on alloy, a word possibly borrowed from tho Persian. The view, held even so early as in Pliny's time, that " bronze " was derived from (aes) Bnmdu6i?ium, has been proved untenable.
3 Cf. K, B. Hofmann's paper in the Zeitschrift Jilr Berg- und Hillt&i- wesen, vol. xli. Nos. 46 — 61. P. Diergart has discussed with much ingenuity and in great detail the question whether Strabo's "Imitation silver" {Scheinsttber ; fyevtiiLp-yvpos) was really zinc, as many have maintained it to be. He comes to the conclusion that it was not (Cf. Journ. pr. Chem., vols. Ixvi. p. 339 ; Ixvii. p. 326 ; Ztschr, Angew. Chem. for 1002, p. 611).
4 Even so early as 300 B.C., " cadmia " was famous as a medicine. The word likewise means " tutty " (oxide of zinc), or also rich zino ore. Accord- ing to K. B. Hofmann, it is not improbable that galmei (cadmia, colamine) is derived from cadmia; i.e. those three terms appear to be synonymous. '
MANUFACTURE OF GLASS 17
from cinnabar by means of copper and vinegar, and terms it " liquid silver." Dioscorides describes the production of mercury, which he at first termed vSpdpyvpos, from cinnabar and iron, i.e. by a process of simple elective affinity, without, however, making the slightest attempt to explain the process. For the carrying out of this operation, an exceedingly im- perfect distilling apparatus was used. Pliny makes mention both of the purification of the metal, by squeezing it through leather, and also of its poisonous nature. It did not escape the Ancients that other metals, gold in especial, were altered by mercury (cf. p. 13) ; indeed Vitruviuw gives a. minute recipe for the recovery of gold in worn-out sewn draperies by this means.
An account will be given later of several metallic com- pounds known in ancient times.
Beginnings of Technical Chemistry among the Ancients.
The Manufacture of Glass. — The art of making vessels from glass originated in China and Egypt, and had for a long time its chief habitat in Thebes ; from there it spread to the Phoenicians and other Eastern nations, the Greeks first acquiring it — so far as actual proof goes — in the fifth century B.C. Pliny is the first to give a distinct account of the preparation of glass by fusing sand and soda together.1 •>"
The artificial colouring of glass by metallic oxides, especially oxide of copper, was discovered at a very early date. Many of. the remains which have been found in Ancient Egypt indicate that the manufacture of glass must at that time have attained to a high degree of perfection, methods for producing enamels and artificial gems being then known. Pliny states that beryl, opal, sapphire, amethyst, etc., could
- * The discovery of glass in Egypt was undoubtedly accidental, soda having been added as a flux to. sand containing gold for the purpose of extracting the latter. For an account of the spread of the knowledge of glass manufacture, cf. Minis' Daa Olos, seine Gfeschichte, etc., in the Ztachr. Angew. Cliern. for 1903, p. 267. ' • - . '
C '
18 FROM EARLIEST TIMES TO THE BIRTH OF ALCHEMY OH.
be imitated, but that at the same time these imitations were distinguishable from the real stones through being softer and . lighter.
The first preparation of glass presupposes in any case an acquaintance with soda or potash ; the former of these was found as a natural product on the shores of certain lakes, e.g. in Macedonia and Egypt, while carbonate of potash was obtained from a very early period by lixiviating the ashes of plants, and also, according to Dioscorides, by igniting tartar. These two salts l were frequently mistaken for one another on account of their similar action. They were largely used' for the preparation of soap, and also directly for washing clothes, cleansing the skin and the teeth (just as the ash of tobacco, which is rich in carbonate of potash, is often employed as a tooth-powder at the present day), and also as ingredients of medicines. Lastly, the ashes of plants and saltpetre were much prized as effective manures.
To the art of pottery must be ascribed an age at least as great as that of the preparation of the noble metals and of glass. Even the old Egyptians , understood how to coat their originally simple earthen vessels with coloured enamel. At a later date the ceramic industry prospered among the Etruscans, and also in many towns of Southern Italy and Asia Minor. Porcelain, which was discovered and employed by ^ the Chinese, remained entirely unknown to the older civilised European nations.
The Manufacture of Soap.-Of no slight interest is the tact that the saponification of fats by means of alkalies with the object of preparing soap— that is to say a com-' plicated process of organic chemistry— was already practised in ancient times. Pliny's records on the subject make it probable that in Germany and Gaul soap was prepared from animal fat and the aqueous extract of ashes, the latter
The Hebrew neter probably denotes soda, while the Latin
MANUFACTURE OF SOAP ; DYEING 19
being strengthened (rendered caustic) by the addition of lime. Further, there was a distinction drawn between soft and hard soaps, according as potash or soda (the latter being obtained from the ashes of shore plants in Gaul) was used in the preparation.1
Dyeing likewise belongs to the arts which the Egyptians, Lydians, Phcenicians and Jews greatly developed. They knew how to fix certain dyes on cloth by means of mordants, alum a playing an important part here ; indeed the dyeing of purple had attained to a high state of perfection among the Phoenicians. Pliny mentions the application both of madder dye and of litmus (the gatulian purple). Indigo blue seems to have been used, both then and at an earlier date, more for painting than for dyeing, but with this exception mineral substances3 were employed as paints. The principal of these in Pliny'a time were white lead, cinnabar, vermilion, smalt,4 verdigris, red oxide of iron and soot. This last, mixed with gum, also served as ink. Numerous recent researches6 have proved that sulphide of lead (galena) formed the basis of the much-used old Egyptian cosmetic mesdem — and not native sulphide of antimony, as was at one time supposed. Mesdem was also a highly prized medicine. The use of preparations of antimony belongs to a later period. The sulphides of arsenic, realgar and orpiment served both as pigments and as medicines, although their poisonous
1 From K. B. Hofniann'fl researches it appears to be doubtful whether the aapo of the Romans meant soap, and not rather a depilatory.
3 Under (Trwr-mpta or alumen of the Anoionts must be understood sub- stances of astringent properties generally, although alum itself is what is usually meant; being prepared from alum shale, it contained green vitriol as an impurity.
3 Of. Kolbert in the Mitthettungen zur Geschichte der Medizin und der NaturwissenachOfften, 1902, p. 277.
4 Davy found cobalt in certain antique glasaes, and assumed from this that smalt had been used in their manufacture. According to Fouqud (Gompt. Rend., vol. cviii. p. 325) Egyptian glass contained only oxido of copper as the colouring material ; but verifiable pigment containing cobalt hasjbeen again found recently in small Egyptian statuary (K. B. Hofmann).
5 Collected and critically examined by K. B. Hofmann in his paper : — U&er Mesd&m (Mittheilunqen dea Vereina der Jirzte in Steiermark, 1894, Nos. 1 and 2).
c 2
20 PROM EARLIEST TIMES TO THE BIRTH OF ALCHEMY OH.
action was known. In short, the Ancients had access to a considerable number of colouring chemical compounds, some of these being the earliest chemical preparations to be manufactured on a large scale.
As has been already indicated, the use of such arti- ficially prepared products in medicine also extends to a period very far back, even although, in referring to this, one can only speak of the first beginnings of a pharma- ceutical chemistry. But a connection between the chemical art and pharmacy established itself very early indeed, e.g. among the Egyptians, who were doubtless the first to employ actual chemical preparations for medicinal purposes. Thus verdigris, white lead, litharge, alum, soda and saltpetre served for the making of salves and other medicaments, while the preparation of lead plaister from litharge and oil was much practised in the time of Dioscorides. Iron rust was a very old medicine, its use being ascribed to .^Escula- pius, while sulphur and copper vitriol containing iron (chal- canthum) were valuable ingredients of the medical treasury before our era ; but the important preparations of antimony and mercury can be proved to have first come into notice in the alchemistic period.
Most of the officinal compounds just referred to were also used for other purposes, as has already been mentioned in a few cases. The combustion-product of sulphur, for instance, was employed for fumigation (vide Homer), for the purification of clothes, the conservation of wine, and for destroying impure colours (Pliny), while copper vitriol and alum were used in dyeing operations. — In closing this short account of the knowledge possessed by the Ancients with regard to chemical compounds, the following substances may be mentioned, substances whose practical application dates from a very early period. In ancient times lime was burnt, and after being slaked, Avas used for preparing mortar, and also, as already stated, for causticising soda (cf. p. 19). Of the acids, acetic acid 1 in the form of crude wine vinegar was
1 The Ancients had the most extravagant ideas with regard to the solvent power of vinegar upon mineral substances, as may be gathered
I ORGANIC SUBSTANCES KNOWN IN ANCIENT TIMES 21
the earliest known, its presence being assumed in all acid plant juices. The mineral acids, which are of such import- ance in technical chemistry, were only discovered in the succeeding epoch.
Other organic compounds known at the beginning of our era, and doubtless even before then, were sugar (from the sugar-cane), starch1 (from wheat), many fatty oils (from seeds and fruits, the oil being extracted either by pressing or by boiling with water), petroleum and oil of turpentine, which last was obtained by the distillation of pine resin in very imperfect apparatus.2 Of the fatty oils, olive, almond and castor oils, etc., were known and used for a variety of purposes, the first-named — e.g. — for extracting perfumes from flowers, leaves, etc. Ethereal oils were also known and employed in large number. — The animal fats played an important part in medicine, and Pliny's mention of sheep's wool grease, among other things, is noteworthy here, seeing that it has recently been brought into use again in the form of lanoline. — Pliny does not seem to have been acquainted with cane sugar ; but one frequently comes across passages in his writings referring to the occurrence and remarkable actions of vegetable poisons (alkaloids).
Such compounds 'as spirits of wine, carbonic acid, etc., which are formed in many processes of fermentation, e.g. in the making of wine, beer and bread, remained unknown to the Ancients. It is true that they noticed in these cases, and also in others — natural emanations of gas, for instance — the presence of a kind of air prejudicial to breathing, and, even under certain circumstances, fatal to life; but it did not occur to them to recognise in this a gas different from atmospheric air.
from the concordant statements of Livy and Plutarch that Hannibal, in his passage across the Alps, cleared the way of rocks by means of it. The story which Pliny tells of Cleopatra may also be recalled here, — how she, in fulfilment of her wager to consume a million sesterces at one meal, dis- solved costly pearls in vinegar and drank the solution.
1 &nv\ov, So called from its being prepared without millstones, and the production of which is described by Dioscorides.
2 Prof. K. B. Hofmann kindly tells me that the earliest account of a destttlatio per descensum is to be found in Aetiufl (Aldine Ed., fol. 10).
22 FBOM EARLIEST TIMES TO THE BIRTH OF ALCHEMY on. I
This lack of the gift of observation, this disinclination to go to the root of any phenomenon, in fact, a certain in- difference with regard to natural events, are characteristics of the attitude of the Ancients towards nature. Instead of experimenting with natural products, they infinitely preferred to call speculation to their aid, so that the most superficial observations gave rise to opinions which, when uttered by high authorities, attained to the dignity of dogmas. How otherwise than from an extreme lack of the deairo of observation can one explain Aristotle's assertion that a vessel filled with ashes will contain as much water as one which is empty ? A further instance of the credulity of that time is given in the conviction expressed by Pliny, and universally held, that air can be transformed into water, and vice versa, that earth is produced from water, and that rock-crystal also proceeds from the latter. The assumption that water can be transformed into earth has often come up again at later periods, having exercised the minds of people even in com- paratively recent times; as it subsequently assumed the form of an important question of dispute, it will be referred to in detail later on.
CHAPTER II THE AGE OF ALCHEMY
IN the introduction to this book Egypt is spoken of as the mother-land of Alchemy. The University of Alexandria was especially instrumental in the propagation of the latter during the first centuries of our era ; it was the carrier and inter- mediary for the alchemistic doctrines, more particularly at the*fcime of the fall of the Western Roman Empire.
The attempts to convert the base metals into the noble ones had their origin in superficial observations, which ap- peared to give a strong support to the belief in this trans- mutation. Among such accidental observations was that of the deposition of copper upon iron utensils left in copper mines, from the waters which accumulated there. What more natural than to conclude that a transmutation of iron into copper had occurred ? For the production of gold or silver from copper, the transformation of the latter into yellow or white alloys by means of earthy substances such as calamine or arsenic appeared to give warrant. Finally, the fact that a residue of gold or silver remained behind when an alloy with lead or an amalgam with mercury was strongly heated, indicated the generation of those noble metals.
To these considerations of a practical nature, which strengthened the conviction as to the transmutation of metals, but which inferred a gross self-deception on the part of the observer himself — to say nothing of their being turned to good account by crafty knaves — there came to be allied, in this epoch for the first time, the tendency to group together chemical facts from common points of view.
24 THE AGE OF ALCHEMY OHAP.
It was precisely in the mode in which it was attempted to explain the composition of the metals that there lay a powerful and ever-active charm, leading to the belief in the ennobling of the baser metals and to continually repeated efforts to achieve this. The first beginnings in an experi- mental direction, which we meet with early in the alchemistic period, although very incomplete, indicate nevertheless a distinct step in advance as compared with the deductive method which had hitherto reigned supreme, and whose fruits consisted, for the most part, in the setting up of mystic cos- mogonies. The few observations which were made remained, however, isolated — that is, were not grouped together in a connected manner.
That the attempts to attain to a knowledge of the processes of nature by the inductive method were but slight at best in the alchemistic period, is explained by the supremacy of the Aristotelian doctrine, which, amalgamated with the Neo-Platonic philosophy, trammelled the minds of men throughout almost the whole of the Middle Ages. Even the Christian theology had to compromise with this system, the product of the joint work being scholasticism, which imprinted its stamp upon all the mental efforts of that time and prevented their free development. The relation of the alchemistic tendencies to the Aristotelian philosophy has been already indicated (p. 9).
The limitation of this epoch between the first appearance of alchemistic conceptions (in the fourth century) and the bold attempt of Paracelsus to call in chemistry to the aid of medicine (in the beginning of the sixteenth century) is thus a natural one, since, during the whole of this time, one and the same keynote runs through all the questions bearing upon chemistry, viz. the idea of ennobling the metals. People were so convinced of the practicability of this for many centuries, that almost every one who devoted himself to chemistry, and many others besides, strove hopefully towards this long-desired goal. The early mixing up of astrological and cabalistic nonsense with these alchemistic endeavours marks very distinctly the degeneration of the latter.
ORIGIN AND FIRST SIGNS OF ALCHEMY
Alchemy by no means ceased to exist on the appearance of the new iatro-chemical doctrines, but gradually receded as chemistry became more of a science. True, its seductive problems are often seen to throw a weird lightning flash on the chemist's camp, and to exercise upon even the most eminent of them an undoubted influence ; but upon the main lines which chemistry has followed ever since the time of Boyle, the phantasies of alchemy have had no appreciable effect. Notwithstanding, however, that this influence was but slight, a short account of the position of alchemy during the last four centuries cannot properly be omitted, and will therefore be added as an appendix to this section of the book.
GENERAL HISTORY OF ALCHEMY.1 Origin 2 and First Signs of Alchemistic Efforts.
The sources from which the belief in the practicability of the transmutation of metals was nourished, and which in the course of centuries gradually expanded into a broad stream of the most mischievous errors, have their origin in the gray mists of antiquity. No actual proof of these must be looked for : we depend, with regard to them, upon mythical and mystical traditions. The first historical sources, too, are small in number and very obscure. But we find among various nations distinct signs of alchemy having been pursued as a 'secret science and having been held in honour.
When one recalls to mind that Ancient Egypt was a
1 Of. Kopp, OfMch. d. Ghemie, vol. L p. 40, et seq.; also hie work, Die Alchemie in ulterer wnd neuerer Ze.lt (Heidelberg, 1886).
a Of. particularly M. Berthelot's Lea Oriyines de, I'Alchimie (Paris, 1885) and his Introduction tt FJfitude de la Ohimie des Anciens et du Moyen-dge (Paris, 1889); also H. W. Schaefer's admirable treatise -.—Die. Alchemie; ihr aegyptiach-griechischer Ursprung, etc. (Fleusburg, 1887: Sohool- oalendar). M. Berthelot has indeed rendered signal service by his publica- tion and critical revision of old alohemistic works, such as the Leyden papyrus, and Greek and Arabic MSS. Comparatively recently, in con- junction with certain philologists, he has given to the world the Collection dea Anciena Alchimiatea Gfrecs and La Ohimie en Moyen-dge.
26 THE AGE OF ALCHEMY OHAI>.
centre of the higher culture, and, especially, that it was a country where the chemical art was practised, one feels no surprise that the earliest reliable records of alchemy are to be found there. Egyptian sources, partly such as have been preserved to us by the Leyden papyrus,1 and partly the writings of the Alexandrians from the third to the seventh century A.D., constitute the most valuable aids at our disposal for a historical proof of the origin of alchemy. The influence of the doctrines and practical recipes contained in these works upon the alchemy of the entire Middle Ages is easily demonstrable.
The tradition according to which, among other know- ledge, the art of ennobling metals had been brought from heaven to earth by demons, was universally diffused in the first centuries of our era ; Zosimos of Panopolis states that the mystical book from which this art was to be learned was termed, x^/iev and the art itself p^eia. This myth doubt- less sprang from one exactly similar which is to be found in the apocryphal book of Enoch; indeed, indications of it are to be met with even in Genesis. The later alchemists were inclined to refer the origin of alchemy to the times before the flood, thinking that a special sanctity would accrue to their art from this great age. Moreover, they wrote down various biblical characters as alchemists, on the authority of certain passages in Holy Writ, for instance, Moses and his sister Miriam, and the Evangelist John. When legends such as these found credence in the Middle Ages, it is hardly surprising that the records as to the origin of this art, which remain to us from ancient times, should have main- tained their authority over a very long period.
The first personality with which the origin of alchemy- is associated is that of Hermes Trismegistos,2 " the three times great," who was said to have been the author of books upon,
/ ™8, imP°^ant doc™ent was f°™<! ™ ThebeB, where it was probably rattan about the year 300 A.D. ; but, with regard to the actual date, ?f its composition, there is no exact record.
2 T^ designation is probably first found in Tertullian (end of the. second century of OITT era). Of. Schaefer, p. 4.
ALCHEMY AMONG THE EGYPTIANS 27
the holy art ; he was, moreover, generally reverenced as the discoverer of all the arts and sciences. The then popular expressions " hermetic," " hermetic writings " and " hermetic art " l recalled this undoubtedly mythical personage even so recently as in the nineteenth century. In Romish Egypt pillars were erected in honour of this Hermes, upon which alchemistic inscriptions were cut in hieroglyphics.
Who then was this Hermes ? One has to seek in him, as ancient traditions almost certainly indicate, the personified idea of strength, i.e. the old Egyptian godhead Thot (or Theuth), which, when endowed with the serpent-staff as the symbol of wisdom, was compared by the Greeks with their Hermes, the latter designation being thus transferred to the Egyptian god.2 Alchemy, as a holy and divine art, whose special task consisted in the preparation of the metals, was kept secret and fostered by the priesthood, the sons of kings alone being permitted to penetrate its mysteries. The esti- mation in which it was held rose in exact proportion with the belief that Egypt owed to alchemy its riches.
When and in what way the influence of other nations made itself felt upon the alchemy of the Egyptians, it is difficult to determine. The Babylonish astrologers, without doubt, undertook the fusion of astrology and magic; in particular, the mutual relations between the sun and planets and the metals, which were taken for granted for so many centuries, were of old Babylonish origin. According to the account of the Neo-Platonist Olympiodor (in the fifth century A.D.), gold corresponds to the sun, silver to the moon, copper to Venus, iron to Mars, tin to Mercury, and lead to Saturn.3 The number " seven " was from time immemorial held
1 Tlie designation "spagiric art" (from ffir<io>, to separate, and iyeipw, to unite) occurs for the first time in the sixteenth century.
- This identity is confirmed by the -fact that, in the inscriptions on the temple of Dakke on the Nile dedicated to Thot, the three names Thot, Hermes and Mercurius occur, the first in hieroglyphics, the second in Greek, and the third in Latin (of. Sohaefer, p. 7).
8 Even in Galen are to be found statements with regard to the influence of the planets upon the metals. Of. also J. Volhard's noteworthy essay : — Zar Qeschichtc der Metalle (Zeits&lmft fiir vol. Ixx).
28
THE AGE OP ALCHEMY OJIM\
sacred in the East, and the fact that only seven planets and seven metals were known had without doubt great significance with regard to the connection which was sup- posed to exist between the two; indeed, the metals were called by the names of the stars up to the end of the eighteenth century.
Certain passages in the works of Dioscorides, Pliny, and the Gnostics enable us to conclude that the transmutation of copper into silver and gold was regarded as an as- certained fact daring the first centuries of our era.1 The "duplication of the metals," which is to be found in the writings of firat-century authors, and which also plays a part in the Leyden papyrus, likewise refers to the transmutation of metals. The designation of this art as " Chemia " probably appears for the first time in an astrological treatise of Julius Firmicus (in the fourth century).
Berthelot has made a careful study of the Leyden papyrus (found in Thebes in the third century A.D.), and has com- pared it with later alchemistic writings. This has led him to the conclusion that an intimate connection existed between the industrial production of the noble metals, the dyeing of fabrics, and the coloration of glass (whence the frequent expressions : — Tingiren der Metalle ; Tinctur&n, etc.). The alleged processes of transmutation, which were currently believed for hundreds of years, consisted in artifices for de- basing the noble metals, but at the same time imitating their appearance as nearly as possible in less costly alloys. It is quite likely that, as time went on, the idea took possession of many minds that the gold and silver were newly created by some supernatural aid. It would thus seem as if alchemy originated in the fraudulent practices of gold- workers.
The records of the study of alchemy go on increasing from the fourth century,much information regarding it being found in the writings of the Alexandrian savants of that time,
1 The Chinese also busied themselves with alchemy at that time, the transformation of tin into silver, and of the latter into gold, being held to nave been actually accomplished.
ALCHEMY AMONG THE EGYPTIANS 29
especially in those of Zosimos, Synesios and Olympiodor. In addition to these, various pseudo-authors, especially pseudo- Democritus, are cited here as witnesses to the spread of alchemy ; the philological-historical critic is not yet, however, in a position to fix the dates at which these works were written. In the Middle Ages people did not hesitate to accept the writings of the false Democritus, and also those of a pseudo- Aristotle, as originating from the ancient philosophers Democritus and Aristotle themselves. The later alchemists also fathered counterfeit writings upon Thales, Heraclitus and Plato, in order to make use of the great authority of those names for their own ends.
Zosiraos of Panopolis, a voluminous author of the fifth century, who was looked upon as one of the greatest authori- ties among alchemists both of that date and of later times, is said to have written twenty- eight books treating of alchemy, of which, however, only small fragments remain. His mysti- cal recipes are quite unintelligible, and yet he disbinctly speaks of the fixation of mercury, of a tincture1 which changes silver into gold, and also of a divine w'ater (panacea). Refer- ence is frequently made to the work of the pseudo-Democri- tus, <f>vo-iK& xai pva-Tifcd. The graphic and mysterious language of Zosimos appears to have exercised a permanent influence upon the works of the later Alexandrians, and also, subsequently, upon those of the alchemists of the Middle Ages.
The end of the fourth century and the beginning of the fifth constitute, without doubt, the period in which the study of alchemy reached its zenith among the Alexandrians ; but the works of Synesios upon alchemy and magic, and those of Olympiodor, who bore the surname of " TTOIIJTIJS," operator, do not yield much certain information with regard to definite operations or to the knowledge of chemical facts. How many works which would have been valuable for the history of chemistry were lost through the destruction of the Serapeum, which marked the completion of the overthrow of
1 The term " mercurius philoNOphonim," which is often found in later \mtings, was first used by Synesios.
306
MSc Lib B'lore 540.9 N06 Q £
30 THE AGE OF ALCHEMY OHAP.
Hellenic culture in Egypt, cannot at this distance of time be estimated. That all acquaintance with chemical opera- tions, and chemical knowledge and skill generally, were not thereby quite exterminated was due to the relations which were before that developed between the Alexandrians and the Byzantine savants ; for, from the sixth century onwards, applied chemistry, which may also be said to include alchemy, found a foothold at Byzantium. Even in Egypt itself the knowledge of chemistry was not completely extirpated by that catastrophe, but continued to exist by fostering certain branches of industry, which, without it, could never have been developed. Lastly, the conviction that metals could be transmuted had fixed its roots too deeply to allow of this art dying a natural death, — an art by which endless riches were to be attained.
The Alchemy of the Arabians.
The germs of chemical knowledge, which had lain hidden in the brains of a few philosophers, attained to a marvellous growth^ among the Arabians, who overran and conquered Egypt in the seventh century; it might have appeared much more likely that they would crush the arts and sciences rather than be the instruments of their resurrection. It was certainly curious that this people, originally strangers to science, should assume the care of it and cause it to flourish m an undreamt-of degree, at a time when culture remained at its lowest ebb in most European countries, and every thing had to give way to the pressure of the conditions produced by the migration of the nations.1
The first appearance of the Arabians in Egypt, where they destroyed much priceless literary treasure by fire, did not seem to herald any such change of opinion. They very soon
words^T^A^r1301^ *?". 6^8ion to *"• Point in the following Z H^ ^T8? ^ °ngmal Semitio stoob' Partia% did away with
« tttST 8m I ^ overwhelmed Europe for two centres, convuC M .it had L been by revolutions. They txirned to the everlasting Greek philosophy, and thereby assisted not only in preset? t of *
ALCHEMY AMONG THE ARABIANS SI
learnt, however, to assimilate the elements of the education of the conquered peoples,1 so that we find (especially after the conquest of Spain, in the beginning of the eighth century) many cities of learning springing. up; to these in the following centuries the European nations; — especially France, Italy and Germany — sent crowds of earnest students, who applied themselves, for the most part, to the study of medicine, mathematics and optics. From the Arabian uni- versities of Cordova and other Spanish cities, where alchemy was also ardently studied, it made its way to the other western nations, among which it attained to its full develop- ment in the thirteenth century.
A renown quite unexampled, and an authority which con- tinued all through the Middle Ages, were attained by the physician and alchemist Dschafar, afterwards known to western nations by the name of Geber. About his life (he is supposed to have lived in the ninth and tenth centuries) nothing is known. It is possible, too, that Geber himself has been sometimes confused with his pupil Dschabir of Tharsis.
There can indeed be no dispute that with the name Q-eb&r was propagated the memory of a personality with which the chemical knowledge of the time was bound up. But the recent researches of Berthelot 2 and his collaborators have proved that the Latin writings hitherto ascribed to Geber cannot have come from him. The oldest of these — the cele- brated Summa Perfectionis Magisterii — was not written before the middle of the fourteenth century ; and the De Investiga- tione Ventatis and 2)e Investigatione Perfectionis MetaUorutn, formerly regarded as genuine, belong to an even later date.
1 Reference may just be made here to the important part played by the Nestorians in engrafting the scientific spirit upon the Arabians, and in enriching them with practical chemical knowledge. Recent researches by Berthelot and others leave no doubt that the Arabians derived from the Syrians ranch — if not indeed the greater part— of their knowledge of chemistry.
• 2 See p. 25, Note 2. Cf. also two papers by Berthelot in the Revue dea deux Mondea, Sept. 15th and Oct. 1st, 1893. The orientalist, Stein- schneider, has also come to the conclusion that the Latin writings, formerly ascribed to Geber, are products of the later Middle Ages.
32 THE AGE OF ALCHEMY OHAP.
In fact, the whole of what were supposed to be Geber's Latin writings are apocryphal.
The Arabic MSS. of the real Geber, which Berthelot's investigations have now brought to light, prove that he did not really profess the knowledge and the opinions with which he has been credited. On the contrary, we find Geber adhering closely to the Grseco-Alexandrian alchemists, and bringing forward many mystical views, c-.g, the belief in the influence of the planets upon the metals. There is no dis- tinct indication in his authenticated writings of the theory of the metals hitherto ascribed to him (see below) ; and, • further, the knowledge of chemistry shown in these is very slight. Geber can therefore no longer be regarded as the author of the Latin treatises with which, up to now, his name has been associated. These writings contain, in fact, the collected knowledge of the four or five centuries after his time.
The disciples of Geber, famous Arabian physicians like Maslema, Rhazes, Avicennti, Avenzoar, Abukases and Averr- hoes, ma}T possibly have exercised a retarding influence upon the development of medical science and of pharmacy. But that some of them undoubtedly advanced the knowledge of chemistry is proved by the remarkable work of the North Persian physician Abu Mansur (Muwaffak), entitled "Book of the Principles of Pharmacology." 1 This work is of the highest value, in that it enables us to form a clear idea of the chemical knowledge of the time (examples will be found in the special part of this book), and it is, besides, the oldest Persian book on pharmaceutics. It is worthy of note that Rhazes distinctly assumes the transmutation of metals, while Avicenna disputes it.
Alchemy among the Christian Nations of the West during the Middle Ages.
The doctrines of the Egypto-Greek and Arabian alchemists gradually penetrated into France, Italy and Germany, certain
1 Edited, with critical notes, by Dr. Aolnmdow of Baku, and published by A. Robert ; of. also E. O. Lippinann's lecture on this work, Ztuclir. Angew. Ch&in. for 1901, p. 640.
n ALCHEMY DURING 'THE MIDDLE AGES 38
Byzantine savants — Michael Psellus among them — also con- tributing to the spread of alchemistic ideas. Eastern in- fluence is recognised distinctly for the first time in the earliest appearance — of which there is clear proof — of an alchemist in Germany at the court of Adalbert von Bremen (about 1063), as recorded by Adam von Bremen ; a baptised Jew named Paul gave out that he had learnt in Greece the art of transmuting copper into gold, and he appears to have imposed upon the above-named ecclesiastical prince. The next certain records of alchemistic endeavours in Germany date from the thirteenth century, at which period alchemy was studied by men famous for their learning, and was conse- quently developed in a high degree.
The transformation of the base metals into the noble by means of the philosopher's stone formed at that date the cardinal point towards which all chemical knowledge was directed. Vinzenz of Beauvais1 (in the first half of the thirteenth century) and. after him, men like Albertus Magnus, Roger Bacon, Arnaldus Villanovanus and Ray- mund Lully, whose chief works belong to the same century, regarded the transmutation of metals as an incontrovertible fact. These maintained that the philosopher's stone did exist, and was endowed with the most marvellous powers (see below), their dogmas being based upon those of the Aristotelians and of the Egypto-Greek alchemists. In ad- dition to these, the most distinguished representatives of chemistry, all of whom .belonged to the priestly class, must be mentioned the famous Thomas Aquinas ; the latter did not indeed materially advance the knowledge of chemistry, but he stood' up at various times for the1 truth of the doctrine of transmutation of metals.
The influence of the four men above-mentioned upon the history of chemistry renders biographical notices of them desirable ; their views upon the alchemisfcic problem, and also their very considerable practical knowledge,' will be discussed under the special sections. Their writings have to be criticised with some caution, since many of the alchem- 1 Vinoentius Bellovaoensis.
D
34 THE AGE OB1 ALCHEMY CHAP.
istic treatises of later times were given out to the world under their names.
Albertus Magnus, or, more properly, Albert von Bollstadt, born at Lauingen on the Danube in 1193, taught philo- sophy, grammar, alchemy, etc., publicly as a Dominican in ifildesheim, Regensburg, Cologne and Paris, and became Bishop of Eegensburg in 1260. He retired, however, to the cloister five years later, and died in the Dominican convent of Cologne after having devoted himself for fifteen years to scientific work. Albertus Magnus was held, both by his contemporaries and still more during the later Middle Ages, as a man of the greatest erudition and 'widest acquire- ments, the degrees of which are given by Tritheim, an author of the fifteenth century, in the following words: Magnus in magia, natwali, major in pMlosophia, maoeimiis in theoloffia. His noble character also earned for him the highest respect. Of his numerous memoirs, the two — De A.lchymia and De Rebus Metallids et Mineralifrus are of the most value for adjudging his position with regard to alchemy.
Roger Bacon was born in Somersetshire in 1214, and studied science, as well as theology, both at Oxford and Paris. The veneration felt by posterity for his marvellous and many-sided knowledge is shown by the title which it conferred upon him of Doctor Mirabilis. Since he did not hesitate to oppose in many points the orthodox beliefs of his day, he was subjected to bitter persecution and penalties. His death probably occurred in the year 1294
His firm belief in the power of the philosopher's stone, not only to transform a million times its own weight of base metal into gold, but also to prolong life, seems to us incomprehensible when contrasted with the otherwise enlightened views which he held and propagated. This undisguised recognition of miracle-working, and this bias towards the marvellous, are directly opposed by the fact that Roger Bacon inculcated the working out of carefully devised experiments as a special kind of research, by which' new data for the knowledge of nature should be acquired.
n ARNALDUS VILLANOVANUS AND RAYMUNDUS LULLUS 36
He is to be regarded as the intellectual originator of experimental research, if the departure in this direction is to be coupled with any one name — a direction which, followed more and more as time went on, gave to the science its own particular stamp, and ensured its steady development. The most important works of Eoger Bacon are the following: — Opus Majus; Speculum Alchemice; and Breve Breviarium de Dono Dei. He did not apparently do much towards the spread and development of practical chemical knowledge.
In the life and work of the two notable alchemists, Arnaldus Villanovanus and Raymundus Lullus, the alchem- istic tendencies of their century are clearly reflected, although much uncertainty exists as to many points, especially in the life of the latter, and also with regard to the works ascribed to Lully. Both of them at all events were held in high esteem, not only during their lives, but also in the centuries following. Arnaldus Villanovanus, whose birthplace is un- certain, practised as a physician in Barcelona in the second half of the thirteenth century. His opinions, however, causing great offence to the priests, he was obliged to flee from there and, after vainly endeavouring to escape persecution in Paris and in various towns of Italy, he at last found an asylum in Sicily with King Frederick II. Summoned to Avignon by Pope Clement V., then seriously ill, he lost his life by shipwreck .on the way thither, about the year 1313. He had special opinions of his own as to the nature and efficacy of the philosopher's stone, and also with regard to the noble metals obtained through its means. Among his writings may be mentioned : Eosarius Philosoph- orum ; De Vinis ; and De Yemenis.
A similarly restless life was foreordained for Raymund Lully, a life which comprised in itself the greatest contradic- tions and eccentricities. Shortly after his death the object of a traditional glorification, Lully possessed among alchemists the fame of having attained to the highest which it was in the power of their art to achieve. The historical critic has a difficult task in dealing with him ; for while, on the one
D 2
36 THE AGE OF ALCHEMY CHAP-
hand, many of the writings ascribed to him are obviously counterfeit, there are, on the other, no sufficient data ^for deciding as to which of the remainder are really genuine. Thus there is very great uncertainty whether the alchemist Baymund Lullyis identical with the famous grammarian and dialectician of the same name, who was called by his admirers Doctor IHuminatisBvmus ; for this view, which has been held by many, is strongly opposed by 'the fact that criticisms of alchemy are to be found in many of the works of the latter.
• Most of the records which we possess of the life of Ray- .mund Lully agree in stating that he was descended from a noble Spanish family, and was born in the year 1235. After leading a dissipated life at the court of Aragon, he abjured the pleasures of the world in his thirtieth year and devoted himself to science. It was probably Bacon and Villanovanus who initiated him into the secrets of alchemy. When somewhat aged, he gave himself up to the conversion of the heathen, undertaking several journeys to Africa for this purpose; his reception there, however, was more than once of the worst, and he was at last stoned to death in the year 1315. Tradition has it that he lived for several years after that date in the unresting study of alchemy but there can be no doubt that this was not the case.
His alchemistic doctrines were very obscure; and still more incomprehensible and hidden in deep mystic darkness are his recipes for the ennobling of the metals. Certainly none of the alchemists who preceded him have ascribed to the philosopher's stone such powers as he did ; for he was able to cry out presumptuously "If the sea were of mercury, I would change it into gold."1 And not only gold, but also all precious stones, and that highest good — health, — together with long life, were to be obtained through its means. Of the writings which are attributed to him, the Testamentum, Codicillus sew Vademecum, and JBocperimenta are regarded by the majority of critics as genuine.
1 Mare tingerem, ei merciirhia esset.
n ALCHEMY IN THE 14rn AND 15m CENTURIES 37
• The earliest of the Latin writings formerly ascribed to Geber (e'.g. the Summa, mentioned on p. 31) may possibly have come into circulation soon after Lully's death. It is worthy of note, and also important for fixing with more or less accuracy the date at which they lived, that neither Albertus Magnus nor Raymund Lully refer to these writ- ings, which grew in repute from the close of the fourteenth century onwards. The information which one finds in the works of the pseudo- Geber is by no means inconsiderable. Great progress is apparent in the recipes given for the making of preparations ; in the use of apparatus such as the water-bath, the ash-bath, and improved furnaces ; and in the description of chemical operations like sublimation, filtration, crystallisation, distillation, &c., &c. All this leaves no doubt on the mind as to the high standard of practical chemical knowledge which the pseudo-Geber possessed. The important question of the constitution of the metals out of mercury and sulphur will be discussed later.
The history of alchemy in the fourteenth and first half of the fifteenth centuries contains no single name which will cbmpare in eminence with those of the above-mentioned philosophers,1 as the alchemists themselves preferred to be called.
This must not be taken as meaning that the supposed art of making gold had died out ; on the contrary, it bore its strangest fruit during that period. If it be desired to connect specific names with the study of alchemy at that time, then the Frenchman Nicolas Flamel, Isaac Hollandus the elder and the younger, Count Bernardo da Trevigo, and Sir George Ripley may be mentioned as among those who were supposed to be in possession of the wonder-working philosopher's stone. These men did nothing, however, to materially advance the knowledge of chemistry.
Alchemy was at this time fostered and protected at m'any of the European courts, for nothing appeared to be more simple than to recuperate embarrassed finances by means of artificial gold. Many documents in the history
38 THE AGE OF ALCHEMY OHAP.
of that century bear record to the frequent disappoint- ments which were certain to come about sooner or later — decrees against the practice of alchemy, threatenings of those who contravened them with the severest punishments, and accounts of discoveries of the most bare-faced imposi- tions. Alchemy found especial protection at the court of Henry VI. of England, in spite of the fact that the kings preceding him had had to pay heavily for their leaning towards the hermetic art, and that a stringent law against it had been promulgated by Henry IV. The consequence of the favour shown to it by these monarchs was the production of large quantities of counterfeit gold which, in the form of coinage, inundated neighbouring countries. Charles VII. of France, who was then at war with England, was seduced by an alchemist, Le Cor, into a similar experiment, and thereby materially increased the debt of his country; to the alche- mistic gold which he set in circulation were added the English " Rose nobles." Counterfeit coining, carried out on such a large scale, was hardly calculated to raise the reputa- tion in which alchemy was held.
The discredit thus attaching to alchemy was extended to chemistry itself, although it is certain that the latter was enriched during this period by many valuable observations and practical results ; towards the end of the fifteenth century, and at the beginning of the sixteenth, we meet with a marked extension of chemical knowledge. Until recently this progress was always associated with the name of Basil Valentine, who was supposed to concentrate in himself all that was known of chemistry at the close of the Middle Ages. And, in truth, the writings ascribed to him show a fulness and ripeness of knowledge in pure chemistry' which are marvellous. But their genuineness has become more and more questioned, and rightly so. For a long time the belief in his personality was maintained ; investigations., which were carried out at the command of the Emperor Maximilian I., appeared to show that Basil Valentine was 3, Benedictine monk of Southern Germany. In respect to the works attributed to him, it was of course conceded that these
n P8EUDO-BASILIUS VALENTINUS 39
had undergone various additions and alterations in the course of the following decades. The works which appeared under his name — a name already in the highest repute at the beginning of the sixteenth century, more especially among alchemists — were published early in the seventeenth century by City Chamberlain Tholde,1 of Frankenhausen, Thuringia, the most important of these being the following : — Twunvph- wagen des Antimonii (" Triumphal Car of Antimony ") ; Von dem grossen Stein der Uralten Weisen (" On the Great Stone of the Ancient Philosophers ") ; Offeiibai^ung der verborgenen Handgriffe ("Revelation of the Hidden Key"); Letxtes Testament (" Last Testament ") ; Schhtssreden (" Con- cluding Words ").
It is unfortunately not now possible to extract from these works the kernel due to the original author ; but, notwithstanding this, there can hardly be any doubt that a large number of facts were recorded by the writer who lived about a hundred years before the books were published, this being especially the case in the " Triumphal Car of Antimony," in which we possess what for that time was a marvellous description of an element and its compounds. The language which he employs is frequently obscured by mystical pictures and alchemistic ideas ; but, while the author thus appears as a visionary on the one hand, he excites on the other our highest admiration from the fulness of his temperate and conscientious observations, as well as from the rational views which he takes of subjects that had up to then, for the most part, been judged erroneously.
1 To call this publisher the "discoverer" of Basil Valentine would, however, be going too far— at all events it cannot be proven ; when,' there- fore, reference has to be made to observations of importance which are ascribed to the latter, we shall speak of a psexido-Basilius. H. Kopp, who in his Oeschichte der Chemie (vol. iii. pp. 110-129) inquired minutely into this question of authenticity, arrived at the conclusion that nothing certain is known either about the author of the above-named treatises or of the dates at which they were written. To all appearance ThOlde's con- temporaries looked upon Basil Valentine's works as genuine.
40 THE AGE OF ALCHEMY CHAP.
SPECIAL HISTORY OF. ALCHEMY. Theories and Problems of the Alchemistic Period.
As already mentioned, the alchemistic ideas, with the transmutation of metals as their leading principle, have been proved to have originated and to have "been first systemati- cally fostered in Egypt. The first attempt to explain this assumed transmutation, -by a theoretical conception of the nature of metals, was made very early. From a ' similar endeavour, i.e. from regarding transmutation — then looked upon as an incontrovertible fact — as a consequence of the constitution of the metals, there sprang the doctrine con- tained in the works ascribed to Geber, which in its essentials predominated during the alchemistic period. It was thus always the metals which gave rise to the early chemical theories.
If we penetrate to the kernel of the doctrines of the Alexandrians through the veil of mysticism which envelops it, ^we see that these philosophers were permeated with the idea that the metals were alloys df ! varying composition. From this it necessarily • followed that 'the transformation 6f one metal into: another was possible, either through the Addition of new metallic substances or the expulsion of some already present. Such transformations of similar sub- stances into one another appear much less wonderful than those of dissimilar ones like air, water and earth, which were mutually convertible, according to the teaching of the Platonists and Aristotelians. The means for bringing about these changes in the metals, the substances which, it was necessary to add to them, and the operations which had to be gone through, were either kept secret or obscured by indistinct figurative language. 'The various colours of the metals, and their alteration by melting them with others, played a prominent part in alchemistic processes ; in impart- ing thereby the colour of a noble metal to a base one, much was supposed to have been attained. For the Alexandrians, therefore, and also for the alchemists of the Middle Ages,
ii COMPOSITION OF THE METALS 41
the colouring of metals was synonymous with their trans- mutation. The chief operations were the so-called Xantlwsis, Leulcosis and Afelanosis, which were compared with the pro- cesses followed in the dyeing of cloth. The old designation of tinctures, for the media by which this transformation was brought about, gives expression to the idea that the latter consisted in a dyeing operation.
As may be imagined, no trace can be found of any distinct chemical conception, or of any knowledge of the actual opera- tions which take place in these transmutations. At the root, however, of these endeavours of the Alexandrian alchemists to produce noble metals from base, lay speculations purely philosophical, which strongly excited and strengthened the belief in the transmutation of metals. These were partly taken from the writings of Plato, especially from his Timceus, which was highly esteemed by the Alexandrians, and partly from the philosophy of Aristotle. Both of those Greeks held the opinion that the (so-called) elements in general were capable of transformation into one another,1 and an extension of this idea led to the assumption that the same applied to the metals. The observations of the supposed generation of noble metals from base, which have been already discussed, were looked upon as proofs of the correctness of this supposition.
, We find among the great Western alchemists distinct views with regard to the composition of metals. Albertus Magnus, for example, assumed arsenic, sulphur and water as their constituents; Arnaldus Villanovanus and Lullus, on the other hand, . mercury and sulphur. Lully, in fact, had no hesitation in stating that every substance is composed of those two things.
• In the writings hitherto attributed to Qeber, but which, according to Berthelot, are not of earlier date than the fourteenth century, we find a specific chemical theory of the
1 This idea comes out very clearly in the following passage from Tinueus: — "We believe from observation that water becomes stone and earth by condensation, and wind and air by subdivision ; ignited air becomes fire, but this, when condensed and extinguished, again takes the form of air, and the latter is then transformed into mist, which dissolves into water. Prom this, lastly, are produced rooks and earth."
42 THE AGE OF ALCHEMY CHAP.
metals, a theory which, supported by the great authority of Geber's name, found universal recognition in the later Middle Ages. This theory looks upon classes of bodies from a chemical point of view, and seeks to explain the difference between the substances comprising these by assuming a peculiar chemical composition. The metals consist of sulphur, and mercury, which are present in them in different proportions and in different degrees of purity.1
The transmutation of metals consists, according to him, in an arbitrary alteration of their composition; the ennobling of them, specially, in a purification and fixation of the mer- cury. The idea of creating a metal anew, which we find highly developed among Western alchemists, is not to be found in the pseudo-Geber's writings. This, together with the application of his theory, is proved by the following sentences, which comprise in themselves his theoretical and practical chemical programme : " To assert that one substance can be produced from another which does not contain it, is folly. Since, however, all metals consist of sulphur and mer- cury, we can add to them the constituent in which they are deficient, or abstract the one which is present in excess. In order to achieve this, make use of the art : calcination, subli- mation, decantation, solution, distillation, coagulation (crys- tallisation), and fixation. The active agents are the salts, alums, vitriols, borax, the strongest vinegar and fire."
The varying origin of the works hitherto ascribed to Geber explains why in many passages of these writings no distinc- tion is drawn between the supposed two constituents of the metals and natural sulphur and mercury, while we frequently find him expressing, in others, the opinion that the former are not identical with the latter. The mercury and sulphur present in the metals were, in this second case, looked upon
1 The pseudo-Geber sometimes added arsenic to the above-named con- stituents of the metals as a third possible one, without, however, laying emphasis upon this extension. Here and there, also, Aristotle's doctrine of the four different states of matter appears to get mixed up with his views upon the composition of the metals, the "four elements" being regarded to some extent as subsidiary constituents, sulphur and mercury being the principal ones.
w DOCTRINES OF THE P8EUDO-GEBER 43
as being of an abstract nature ; thus • mercury conferred lustre, malleability, fusibility, and what we consider metallic properties generally, while sulphur, on account of its com- bustibility, was regarded as being present because of the alteration of many metals in the fire. The noble metals, those which withstood the fire, therefore consisted of almost .pure mercury, which however could not be identical with the ordinary substance of that name, since the latter was volatile; this property was ascribed to the fact of ordinary mercury containing sulphur. By means of these and similar assump- tions, contradictions between theory and facts were easily set aside, the alchemists of later times especially distinguishing themselves in this way.
For the solution of the possible problem of the transmuta- tion of metals — possible, that is, in the sense of the above theory, — so-called " medicines " are, according to the pseudo- Geber, requisite, these being distinguished as possessing different power and virtue. The medicines of the first order do indeed produce changes in the base metals, but these changes are not permanent. Those of the second order parti- ally alter the properties of such metals into those of the noble ones,1 but the transmutation proper is only effected by the medicine of the third order, which is variously designated as the Philosopher's Stone, the Grand Elixir, or the Magisterivm (masterpiece).2 The accounts which the pseudo-Geber gives of the preparation of the medicines of higher order are wholly unintelligible ; it should, however, be emphasised that there is a wide difference between these and the incredible ex- aggerations of which other alchemists were guilty, when speaking of the efficacy of such secret preparations.
One cannot but feel surprised that the alchemists of the thirteenth and fourteenth centuries, possessing as they did a fairly extensive knowledge of chemistry, should have re- mained satisfied with such speculations as to the constitution
1 The Particulars, of the later alchemists appear to have corresponded to medicines of the second order.
3 At a later period the great elixir was distinguished from the small one, which only transmuted the base metals into silver.
44 THE AGE OF ALCHEMY OHAP.
of the metals, without actually trying to isolate the sub- stances that they assumed as being present in these and other bodies. Instead of endeavouring to gain an insight into their composition by experiment, they brought forward fresh hypotheses to controvert obvious objections, e.g., that the above-mentioned constituents (mercury, &c.) were not identical with the substances commonly so named.
. The above theory of the metals underwent an extension, probably in the fifteenth century, by the assumption of the presence in them of a third constituent, viz. salt ; we find Isaac Hollandus speaking of a " saline base (Qrundstoff) of the metals," and come into closer contact with this idea in the works of the pseudo-Basilius, and in those of the latro- chemists of the sixteenth century. By the term salt was not meant a definite chemical compound, such as common salt, but rather the principle of solidification and power of with- standing fire, just as sulphur determined the combustibility or change in the fire and also the colour, and mercury the metallic character and volatility. The opinion was genera- lised by the assumption of these three essential principles in all substances, an assumption which Paracelsus made the basis of his iatro-chemical doctrine.
- Their views upon the composition of the elementary bodies being so very obscure and so utterly erroneous, one sees' how it was impossible for the alchemists to explain chemical processes rightly, connected as these are with the formation of compounds. Some very, incomplete attempts were made to give a theoretical explanation of isolated observations, but these only led to gross errors creeping in ; the calcina- tion of the metals, for instance, was supposed to depend upon the escape of moisture or of some other constituent, an idea which reappeared .in another form in the later theory of phlogiston. The above theory of the composition of metals is sufficient evidence of the small amount of trouble which was taken to find out the true chemical constituents of bodies.
. We may safely say that scientific chemistry only really began with the fruitful endeavours to discover the real com-
THE PHILOSOPHER'S STONE 45
position of substances. It is out of the question to speak of this as applying to a time when it was considered as proved that the .formation of a chemical compound was identical with the annihilation of its original components, a new substance being created. This view was the almost ' sole predominating one during the later alchemistic period, although in the works of the pseudo-Geber we find some indications of more correct opinions on the composition of many chemical compounds (the recognition of mercury and sulphur, for instance, as constituents of cinnabar).
Contemporaneously with the holding of such theories, based upon no facts whatever, the Western alchemists strove in every imaginable way to obtain the philosopher's stone, — mcrcurius philosophorum.1 Those -of them who were in happy possession of the means for transmuting metals, attributed to it the most astounding powers. In order to give some idea of the aberration of mind caused by the alchemistic problem, a few of the extraordinary assertions of well-known alchemists with regard to the preparation and efficacy of the philosopher's stone may be mentioned here.
For its preparation (we are now speaking more particu- larly of the thirteenth century onwards) a onateria prima was requisite, to obtain which was the hardest task of all. The most incredible substances, natural products of every kind, were taken as raw materials for the manufacture of this preparation, and worked up in every conceivable way. Those who laid claim to the possession of the philosopher's stone took very good care to keep the secret of their materiel, prima to themselves. They described all kinds of operations with it 2 in the most enigmatical recipes, employing at the same time mystical drawings, such as those of the dragon, the red or green lion, the lily, the white swan, &c., and well knew how to keep their imitators, of whom there were formerly shoals (isolated cases being found even in the 19th century),
1 Cf., in addition to the works enumerated in Notes 1 and 2, p. 26, the Engler lecture :—Der Stein der Weisen (Carlsruhe, 1889).
3 The process of fixation, a term which indicated the solidification of mercury by the transmutation, was of special importance.
46 THE AGE OP ALCHEMY OHAP.
in a state of continual tension. That this was possible is explained by the immovable and almost universal belief in the transmutation of metals, by means of the philo- sopher's stone, during the Middle Ages.
To the latter the greatest miracles were ascribed ; thus, Roger Bacon does not hesitate to say that it was able to transform a million times its weight of base metal into gold (millies millia et ultra). Others, e.g. Amaldus Villanovanus, were more modest in their estimate of its powers, stating that it could convert into gold one hundred times its weight of mercury. Others, again, surpassed even Bacon, as the following passage from the Testa/nientum Novissiinv/m, ascribed to Lully, proves: "Take of this precious medicine a small piece, as large as a bean. Throw it upon a thousand ounces of mercury, and this will be changed into a red powder. Put one ounce of the latter upon one thousand ounces of mercury, which will thereby be transformed into a red powder. Of this, again, an ounce thrown upon a thousand ounces of mercury, will convert it entirely into medicine. Throw an ounce of this on a thousand ounces of fresh mercury, and it will likewise turn into medicine. Of this last medicine, throw once more an ounce upon a thousand ounces of mercury, and this will be entirely changed into gold, which is better than gold from the mines." One sees clearly, from these and other fraudulent assertions, that the simple standpoint which the Egypto-Greek alchemists assumed, with regard to the question of the transmutation of metals, was departed from in the later Middle Ages.
In view of such excesses, which are an insult to the human understanding, it causes no surprise to find attributed to the philosopher's stone other results which are, if possible, even more incredible ; being a universal medicine, health and life were to be preserved and ensured by it. State- ments as to the power of prolonging life possessed by the elixir were also rife in the later Middle Ages, and it was no unusual assertion that adepts, the fortunate possessors of the panacea, had been able to prolong their lives to 400 years and more. The long lives of the patriarchs were explained
n THE PHILOSOPHER'S STONE 47
by the assumption that they were acquainted with this universal medicine. In the time of the Arabian alchemists healing properties were ascribed to gold prepared artificially and brought into the potable form (aurum potdbile), and from this the belief in the medicinal power of the philoso- , phe'r's stone appears to have originated.
Alchemistic ideas produced their most absurd results towards the end of the Middle Ages and in still more recent times, the creation of living beings by means of the philo- sopher's stone being not merely held as possible, but being actually taught; this marks the acme of the mental aber- ration they induced,
The melancholy picture, which the condition of alchemy presents to us at various periods, becomes still more sombre and involved in deeper shadow from the fact that men did not hesitate to affirm the Divine assistance and to claim predestination, in order to explain the marvellous effects of the philosopher's stone. Gross abuse was made in this way of the name of the Deity, and also of prayers and biblical quotations, by the alchemists of the thirteenth century, and still more by their successors. There is no need to go into further detail upon this point here, but it is necessary to mention it in order that the methods by which the problems of alchemy were treated at different periods may appear in their proper light.
Upon the development of chemistry as a science, the alchemistic doctrines — especially the theories of the composi- tion of metals — had only a slight and an indirect influence. The excesses to which they gave rise have — as aberrations of mind, enchaining a large portion of the educated — a higher value for the history of civilisation than for that of chemistry. The main significance of alchemy for the latter lies in this, — that the endeavours to solve the problem of the transmutation of metals were the cause of actual work with materials of every kind; and the result of this was a not inconsiderable increase in the knowledge of applied chemistry during the alchemistic age. The following section will be devoted to an account of the latter.
48 THE AGE OF ALCHEMY at
Practical-Chemical Knowledge in the Alchemistic Period.
When one considers upon what superficial observati the conviction of the transmutability of metals was bas and how readily wholly untenable theories upon the cc position of bodies were brought forward and accepted, < feels no surprise that comparatively little progress - T made during the succeeding epochs towards explaining • numerous chemical processes already known to the Anciei The acquirements in, chemistry during these centuries the selves likewise remained, for the most part, empirical; was but seldom that the composition of chemical compou] was even in some degree correctly indicated. The fanta* treatment of chemistry — a treatment wholly foreign to exact sciences — has been sufficiently detailed in the preced: section. We must not omit to mention, however, that • addition of new facts to those already known, and the g of experience in the fields of technical and pharmaceuti chemistry and in the manufacture of chemical preparatic were not inconsiderable.
Technical Chemistry. — Metallurgy, upon which 1 infant powers of an early developed technique were expend shows, upon the whole, but little progress. In the secc half of the alchemistic period more was learnt of some of 1 metals already known, while certain others were discover e.g. the semi-metal antimony, together with bismuth a zinc ; but these can only lay claim to a subordinate positi in the circle of metallurgical processes generally. Fr the eleventh century on, mining increased among 1 Western nations, in Germany especially in the Harz, Nass and Schlesien. So far as our present information goes, o] trifling alterations were made in the preparation and pur cation of the metals.2
1 Of. Kopp, Gfeseh. d. Chemie, vols. iii. and iv. ; Hb'fer, jjwtotre, < voL i. p. 317, et aeg. ; Gmelin, Gesch. d. Ohtmie ; Berthelot, La Trc mission de la Science Antique du Moyen-dge ; and von Lippman's inter* ing lecture Ohemische Kenntni$ae vor 1,000 Jahren (Ztschr. angew. Ghe, for 1901, Part 26).
'J The -work entitled Schedula Diversarum Artium, which was written
ii METALLURGY 49
Gold was obtained and purified from other metals and admixtures by the old method of cupellation (working with lead), already accurately described by the pseudo-Geber. The latter knew that the desired result was ensured and its pro- gress hastened by the addition of saltpetre, and, further, that copper and tin, but not silver, could be separated from gold in this way. Subsequently there was. added to this the process of purifying gold by fusing it with antimony tri- sulphide ore (Spiessglanzerz). Alloys of gold were often fraudulently prepared of set purpose.
The extraction of silver from its ores was accomplished, as in Pliny's time, by fusion with lead, an operation termed " Aussaigern." The only means of separating gold from silver, which was known up to a comparatively recent date, was the cementation process of the Ancients. The wet process with nitric acid appears to have been first successful in the time of Albertus Magnus, at least he is the earliest to indicate it ; an absolutely certain acquaintance with the process is first to be found in'Agricola.
From the importance which was attached to the successful working-up of gold and silver ores, one understands how the closest attention was given from an early period to the definite quantitative yield of the noble metals. Accurate balances came into use, their employment in cupellation and cementa- tion processes being made obligatory by law ; one thus meets here with the first beginnings of a docimacy.
With regard to the metallurgy of iron, lead, tin and copper in the alchemistic period, there are no particular
Theophilus Presbyter, a Benedictine of the eleventh century, gives a true picture of the state of technical industry in his time, particularly of the working up of metals, something being also said about their production from the ores. It is worthy of note that Arnold Bb'cklin made use of this ancient book, •with its recipes, in his partly successful attempts at pro- ducing beautiful and at the same time permanent pigments (of. Frey's "A. BScklin"). A Latin manuscript of the eighth century, Compositiones wL Tinguenda, enters into minute details upon dyeing and upon the appli- cations of colours generally. Another tenth-century manuscript, Mappos Glamcida, edited by Berthelot, contains an essay on the noble metals and, by its agreement with recipes found in the Leyden papyrus, conclusively shows the close connection with the Egypto-Greek alchemy.
E
50 THE AGE OF ALCHEMY OHAP.
improvements to record. The different degrees of hardness and softness of iron were early known ; thus in the tenth century Abu Mansur emphasises the fact that the purest iron is the softest. Again, so far back as in the fifteenth century copper was obtained by the wet process as the so-called cement copper, by precipitating a solution of copper vitriol with iron. The changes undergone by these metals on. being heated and on treatment with chemical reagents, especially acids, were closely studied, and thus the know- ledge of metallic preparations was decidedly enlarged (see below). Whether metallic zinc was known and used in the early Middle Ages cannot be stated with certainty, although there are many accounts which favour this view, e.g. that of Abu Mansur (cf. the reference to the imitation silver of the Ancients, tyevBdpyvpos, p. 16, note 3). Diergart1 contends that zinc was known in those days.
Mercury, which played such an important part in the theoretical views of the alchemists, was prepared on a large scale for technical purposes by roasting quicksilver ores in improved fufnaces, especially after the opening up of the rich Idrian mines in the fifteenth century. The prepara- tion of the metal by distilling a mixture of sublimate and caustic lime was also known. For its purification various processes are given, some of which had been already de- scribed by the pseudo-Geber. Mercury was much used, particularly for the extraction of gold and silver (by the so-called amalgamation process) and for gilding.
Metallic zinc and bismuth, and also cobalt ore, are like- wise sometimes mentioned, but the metals themselves do not seem to have been employed technically; certain pre- parations of zinc, however, were.
In pottery and glass manufacture, important improve- ments in single points were made during the alchemistic period; but it is also noticeable here that the interest in the chemical process remains a purely external one, no attempt being made to give a scientific explanation of the
1 Mittlwilungen zur Geschichte der Medizin und Natunoisaenach^ften^ vol. ii. p. 147 et seq.
ii CONDITION OP PHARMACEUTICAL CHEMISTRY 51
facts empirically arrived at. The general use of glazes con- taining lead and tin for earthenware vessels is worthy of mention, as is also the burning of colours into glass Cthe entire mass having formerly been coloured by the addition of metallic oxides during fusion).
Dyeing remained stationary on the whole, so far as the chemical media for fixing the colour on the fibre were con- cerned ; alum was universally employed as a mordant, being manufactured on a large scale in different places. The introduction of the kermes dye (cochineal) into European countries by the Arabians, that of orchilla (already known in ancient Rome) from the East in the thirteenth century, and, lastly, the gradual supplanting of the (blue) dye from woad by indigo, are the most important technico-chemical events in the domain of dyeing.
Condition of Pharmaceutical Chemistry.
From the fact of the Arabians and the later Western savants busying themselves with . chemical operations, and thus attaining to preparations of the most various kinds, the pharmaceutical chemistry of that period profited greatly ; here and there we meet with attempts to apply chemical preparations to medicinal purposes. The opening up of the intimate connection existing between chemistry and medicine, which led to the high development of phar- macy, was reserved for the period of iatro-chemistry. The Arabians prepared their medicines strictly accord- ing to the recipes of Galen, Andromachus and others, which were transmitted to them, according to Leo Africanus, by the Nestorians.1 Apothecaries' shops, in which the remedies were almost exclusively prepared from vegetable substances, sprang up at an early date. To the Arabians belongs the credit of having improved and rendered the process of distillation serviceable for this purpose ; distilled water, ethereal oils, and other products (especially spirit
1 For their influence upon the Arabians, see note 1, p. 31.
E 2
62 THE AGE OP CHEMISTRY OHAP.
of wine) obtained by distillation, to which the most wonder- ful results were ascribed, came by degrees into general use.
These apothecaries' shops with their fittings then spread into Spain, Southern Italy (into Salerno in the eleventh cen- tury) and, somewhat later, into Germany. The recipes of that time for the preparation of medicines, the imperfect •pharmacopeias,1 show that the doctrines and axioms of Galen and of the Arabian physicians remained the standards up to the end of the fifteenth century. The position of the physician with regard to the apothecary was early fixed by legal statute, it being considered advisable to draw a sharp distinction be- tween the man who had to prescribe the medicines and the man who had to make them.
In addition to those medicines already in use, many others — more especially metallic preparations — were gradually added ; thus, Abu Mansur mentions oxide of zinc and white vitriol as being employed in the treatment of wounds and for ailments of the eye, and mercury (grey salve), cinnabar, and corrosive sublimate for diseases of the skin. In the sixteenth century preparations of mercury and, more parti- cularly, of antimony acquired great importance in the hands of Paracelsus ; but almost all the physicians of that time took up an antagonistic position with regard to the last of these, being, of opinion that the undoubted poisonous pro- perties of antimony compounds were incompatible with their internal use. Several other pharmaceutical preparations will be mentioned in the following section.
Knowledge of the Alchemists with regard to Chemical Compounds.
It has already been mentioned that the knowledge of the true composition of chemical compounds was but slightly extended during this period ; we have therefore to deal here with the state of empirical knowledge as affecting substances prepared artificially, together with a few occurring naturally.
1 The first German pharmacopeia (Arzneibuch) was drawn .up by Ortholph von Baierland and appeared in 1477.
ii KNOWLEDGE OF CHEMICAL COMPOUNDS 63
The tendency to group together observed facts under a common point of view showed itself at an early date with respect to salts, of which a large number were known. The pseudo-Geber regarded solubility in water as a general charac- teristic ; subsequently the generic name sal was made to in- clude a variety of substances, e.g. the vitriols, potash, soda, saltpetre, alum, etc. Other chemical compounds of totally different nature, viz., the alkalies and acids, were added to the class of salts by many alchemistic writers, the term sal being thus widely extended and distorted; it was reserved for a later century to fix it without any ambiguity. In addition to the common designation sal for a number of heterogeneous bodies, we find in the writings of that time the generic name spiritus for the volatile acids, e.g. spiritus salis for hydrochloric acid ; also the name spiritus urince for volatile alkaline salt (car- bonate of ammonia). The individual salts are distinguished by the word which follows sal, for instance, sal 'petree^ sal maris, etc. ; for alkalies, such as caustic potash, the expression nitntm alcalisatum is frequently used. One seldom meets in the alchemistic age with a strict distinction between potash and soda, or between their carbonates, while, on the other hand, preparations of carbonate of potash obtained in different ways were regarded as dissimilar products.1 ' The distinction drawn by Abu Mansur between "Natron,1" i.e. the soda found in Nature as a mineral deposit, and " Qlialia," the alkali from the ashes of land plants, is, however, very noteworthy (see von Lippmann's lecture). These names have been perpetuated in the German words Natron and Kali.
This acquaintance with the carbonates of soda and potash was accompanied by a knowledge of the lyes obtained froin them by the addition of lime, the strongly alkaline and solvent power of these lyes being largely made use of, e.g. in the pre- paration of milk of sulphur. The name " alkali " is first met with in the Latin writings ascribed to Geber, while the designation "caustic" had been already employed by
1 The salt from the ashes of plants was termed sal vegetable, and that from tartar, soZ tartari.
><; 54 THE AGE OF ALCHEMY CHAP.
;lj
;• Dioscorides for burnt lime, and at a much later period for
|'i lyes. The question of the occurrence of alkalies in plants
:j was frequently discussed among the alchemists ; although it
ij did not escape some of them that different amounts of ash
;ij and of alkali were found in different parts of a plant, only a
':'• few held the opinion that the alkali was really present in the
:• plant itself, most of them believing that it was first produced
'. l! during the incineration of the latter.
i;i 'Until comparatively recently it was thought that the
;,|! Arabians possessed a very considerable knowledge of the
:i;i acids, in comparison with that of the Ancients, who were
i:i: totally unacquainted with the mineral acids. This assump-
j i| tion was based upon the fact that in the treatise De Inven-
;|| tione V&ritatis, attributed to Qeber, he explained the method
;|j of obtaining nitric acid by distilling a mixture of saltpetre.
Ij;' copper vitriol, and alum in certain proportions; it was
!. designated aqua dissolutiva or aqua fwtis. We know now,
;|; however, that this manuscript does not date 'further back
'•!, than the fourteenth century. That no mention of mineral
:!: acid is made by Abu Mansur in his treatise (see above) is at
|J! once explicable by the fact that this was unknown in the
•ji tenth century. The preparation of nitric acid from saltpetre
ij i and sulphuric acid was known to alchemists of a later date.
;! i Sulphuric acid was certainly obtained by the pseudo-Geber.
i| for he mentions as noteworthy that when alum is strongly
II heated, a spirit distils over which possesses a high degree oi
:; solvent power; he does not, however, appear to have investi-
|j gated its properties more closely. Later writings show that
; the preparation of sulphuric acid by distilling a mixture
i of iron vitriol and pebbles, and by setting fire to sulphui
| after the addition of saltpetre to it, was also known. An
I aqueous solution of sulphurous acid, the combustion product
i proper of sulphur, was frequently confounded with sulphuric
acid
; The preparation of aqueous hydrochloric acid, termed spiritus salts, by heating a mixture of common salt and green vitriol, and also its behaviour towards many of the metale and their oxides, only became known at a considerably latei
ii NITRIC AND HYDROCHLORIC ACIDS ; SALTS 65
date. The mixture of this acid -with agua fortis was the so- called aqua regis, now termed agua, regia, which the pseudo- Geber had already made use of, obtaining it by the solution of sa'lmiac in nitric acid.
Nitric acid and aqua, regia l (so-called because it dissolved gold, the king of metals) were highly prized by the alchemists of the West. The observation that almost nothing was able to withstand this aqua, regia, even sulphur being " con- sumed " by it, strengthened the conviction that in it they possessed a liquid which very nearly approximated to the long-sought-for " alkahest," the universal solvent. On the same grounds oil of vitriol was greatly valued, many indeed regarding it as the sulphur philoaophorum, or, at least, as a substance which would lead to the acquirement of the mat&ria prima.
Among the salts which were already known in Pliny's time, and whose properties were carefully investigated by the alchemists, alum and some of the vitriols deserve special mention, the former being obtained in various places from alum shale. The pseudo-Geber tells us how to purify it by recrystallisation from water, and terms it alumen de rooca (from the name of its chief source, the town Roccha), a term which long remained in vogue in France as alun de roche. The fact that alum contained an alkaline salt was overlooked, and its true composition remained unknown ; alum itself, however, was early made use of as an astringent and styptic (cf. Abu Mansur). Iron and copper vitriols were largely employed in different chemical operations. The pseudo- Geber describes the preparation of the pure products by crystallisation ; and the production of iron vitriol by dissolving iron in sulphuric acid was probably known towards the close of the Middle Ages.
The important salts, saltpetre, salmiac, and carbonate of ammonia, first became known and used for chemical purposes in the alchemistic period. The author of the works ascribed to Geber was well acquainted with potash saltpetre, as it
1 Albertus Magnus terms them respectively aqua pri-ma and aqua secwnda.
56 THE AGE OF ALCHEMY CHAP.
served him for the preparation of nitric acid ; and there is every reason to suppose that it was used in even earlier times for the production of fire-works and such like things, after its property of deflagrating with red-hot carbon had been recognised. The oldest designations for it in Roman characters were sal petrce and sal petrosum. Raymund Lully also termed it sal nitri, but distinguished between it and nitrum, the fixed alkali of the older writers ; in the sixteenth century this latter word was converted into natron, while the name nitrum was given to potash saltpetre.
The same applies to the term salmiac, sal ammoniacum, as to that of nitrum, in so far that both of them had originally a different meaning from what they now possess ; for the sal ammoniaciLm of the Ancients was without doubt rock-salt. At the time when the pseudo-Geber's works were written, on the other hand, this name, which is also metamorphosed into sal armeniacum (Armenian salt), could only mean salmiac. Even so early as in Abu Mansur's time we find salmiac in use as a sedative. At first this salt appears to have been partly prepared from dung, and partly to have been found as a natural product of volcanic origin.
Carbonate of ammonia, well known to the alchemists of the thirteenth century as volatile alkaline salt (spiritus wince),. was obtained by distilling putrefied urine. The pseudo- Basil Valentine taught how to prepare it from salmiac and fixed (carbonated) alkali, a method which led a long time afterwards to the proper recognition of the composition of the salt. The pharmaceutical use of these two ammonia compounds, just named, probably belongs to a later date.
The knowledge of the metallic salts was very decidedly increased during the alchemistic period. A special interest attached to a solution of gold in aqua regia, since from this aurum potabile the most wonderful medicinal effects were expected. The pseudo-Geber was the first to become ac- quainted with nitrate of silver in the crystalline state, and to observe the precipitation of its solution by one of common salt, a reaction which came to be applied as a test both for silver and for salt. The alchemists were also aware of the
ii SALTS OF THE METALS 57
beautiful precipitation of metallic silver from a solution of its nitrate by means of mercury or copper.
Compounds of mercury early attracted the interest of those who carried out chemical operations. The pseudo- Geber described the preparation of mercuric oxide by calcin- ing the metal, and that of sublimate (mercuric chloride) by heating a mixture of mercury, common salt, alum and salt- petre; he also taught how to prepare various amalgams.1 Basic mercuric sulphate was known towards the close of the fifteenth century, as was also mercuric nitrate, the latter being soon made use of in medicine.
Preparations of zinc (e.g. the oxide and zinc vitriol) were- used by the physicians of Arabia so far back as the tenth century. There are, however, no detailed records of the formation and properties of preparations of bismuth, although some of these were known towards the end of the fifteenth century. Antimony and many of its compounds must cdr- tainly have been well known at the same period. Although it is not possible to fix an accurate date for the works of the pseudo-Basil Valentine, most of them in all probability contain portions of the original fifteenth century writings,, and reference will therefore be made at this point to two which deal with antimony. In his treatise, Triwnphwagen des Antimonii (" Triumphal Car of Antimony ") the author shows how to prepare antimony itself from the native sul- phide (which was termed antimonium or stibium, and was known to the Ancients) by fusing it with iron. In his treatise, Wiederholung des grossen Steins der Uralten Weisen a ("Recovery of the Great Stone of the Ancient Philosophers "), he writes : " If one adds some iron to the fused Spiessglas*
1 This word is first found in the writings of Thomas Aquinas, who supported the idea of the transmutation of metals with acute reasoning based upon physioal grounds. The part played by amalgams in the transmutation of metals has been already considered.
3 Abu Mansur (tenth century) gives a description of antimony itself, while articles of antimony bronze have been found along with prehistoric remains.
3 This designation of pseudo-Basil Valentine's for native sulphide of antimony became altered later into Spiessglanz.
60 THE AGE OP ALCHEMY CHAP.
that the formation of several metallic sulphides from their components had been observed {e.g. that of cinnabar from quicksilver and sulphur), and this may be supposed to have- contributed materially to a knowledge of their composition. Realgar and orpiment were well known to the Arabian physicians.
In apite of many unequivocal observations to the contrary, people still held to the assumption — widely diffused towards the close of the Middle Ages — that the metals and almost all other substances contained sulphur. Organic bodies,, too, had to conform to this hypothesis; their real con- stituents remained hidden, no sharp general distinction being drawn between them and inorganic compounds. The meagre attempts made to explain the formation of organic substances, e.g. in fermentation processes, only give evidence of confused and untenable views. The organic preparations which were known in the alchemistic age were but few in number. Among them spirit of wine1 takes a prominent place, its manufacture being gradually simplified and im- proved after more perfect apparatus had been introduced by the Alexandrians. In accordance with its importance for medicinal and alchemistic purposes, it was usually termed agy,a vitce, the name alcohol being first met with in Libavius (end of the sixteenth century). The preparation of concentrated spirit of wine — as an excellent solvent for many things — by repeated distillation, and also by dehydration with fused potashes, was already known to Eaymund Lully. The pre- scription for testing its strength was that a portion should be burnt, in order to see whether any water remained behind 01 not. Yarious chemical transformations of alcohol were also well known at the close of the Middle Ages, even though the resulting compounds were not obtained in a state oi purity ; among these were the production of common ether by 'the action of sulphuric acid, and of nitric and hydro-
1 Berthelot (Ann. Chim. (6), vol. xxiii. p. 433) has traced with great care the history of the discovery of spirit of wine, and has found that the preparation of alcohol by distilling wine was accurately known BO far back as the time of Marcus Grteoua (eighth century A.D.).
ii ALCHEMT DURING THE LAST FOUR CENTURIES 61
chloric ethers by the action of nitric and hydrochloric acids respectively. By the " sweetening" ( V&rsr&sswrug) of alcohol is to be understood our term etherification. That alcohol is only formed during the various processes of fer- mentation, which yield wine, beer and spirits, was not perceived even by the most acute observers of that time ; its pre-existence in unfennented materials was thus taken for granted.
Increasing attention was likewise paid to the product of the acetic fermentation. The alchemists of the later Middle Ages taught how to concentrate vinegar by distillation, and they also prepared various salts of acetic acid, e.g. basic acetate and sugar of lead. Other organic acids, too, were noticed in different plant juices, but they were frequently mistaken for acetic acid. Abu Mansur describes several vegetable acids as differing in taste and in properties, more •especially the tannic acids obtained from the fruits and •other portions of plants. He also states in his book (p. 28) that cane sugar had long been known as a medicine. The addition to the medical treasury of various resins and oils, •especially ethereal oils, which were obtained from plants by •distillation in improved apparatus, is no evidence of scientific progress ; this really begins for organic chemistry with the discovery of methods for arriving at the composition of organic compounds.
The Fortunes of Alchemy during the last Four Centuries.
More especially after the beginning of the iatro-chernical period, alchemy gradually became separated from chemistry, which was raising itself to the rank of a science. Although, therefore, a record of the alchemistic aims or rather errors of the last few centuries does not properly come within the scope of a short history of chemistry, they cannot be passed over in complete silence ; the justification for this lies in the rela- tions in which the most eminent chemists of the sixteenth and seventeenth centuries stood with regard to alchemy. The support given by such men to the latter undoubtedly
62 THE AGE OF ALCHEMY CHAP.
accounts to a large extent for the belief in the transmutation of metals as an incontrovertible fact being but seldom affected, and this notwithstanding the great increase in chemical knowledge. Another effective means by which the life of alchemy was prolonged consisted in the favour with which it was regarded by many princes ; the seductive pros- pect of easily acquired treasure often rendered the latter a prey to designing alchemists.
The actual decay of alchemy, for which the numberless disappointments of honest workers and the exposure of numerous frauds paved the way, may be dated from the first half of the eighteenth century, when the conviction of the practicability of transmuting metals began to die out among most chemists. Even up to the nineteenth century, however, we find able and educated men in the thralls of alchemistic chimeras, and directly opposing the simplest rules of reason.
A distinction must be drawn during the iatro-chemical period between alchemists and chemists, inasmuch as the latter aimed at the solution of a scientific problem, viz. the knowledge of the relations between chemistry and medicine. At the same time this distinction must not be taken as meaning that the most eminent among the iatro-chemists were not firmly convinced that the ennobling of metals was a fact, indeed some of them maintained that they were in possession of the most powerful alchemistic specifics ; it was but seldom, however, that chemists were at the same time practical alchemists.
Paracelsus, who was greatly given to romantic exaggera- tions, claimed for himself the widest knowledge of alchemy. Van Helmont, whose authority was especially weighty, went so far as to describe in detail the transmutation of mercury into gold and silver, as effected by himself with the aid of a very small quantity of a gold- and silver-producing philo- sopher's stone. The opinion held by the highly esteemed Libavius respecting alchemy and what it could effect is equally significant of the judgment of that period upon the subject; he regarded the transmutation of metals as an
li POWER OF THE PHILOSOPHER'S STONE 6£
accomplished fact. Other influential physicians of the six- teenth century, such as Agricola — famed as an observant and accomplished metallurgist, — Sennert, and Angelus Sala, were more cautious in their assertions with respect to alchemy, but they never seriously contended against the possibility of transmutation. Tachenius alone, the last iatro-chemist of note, took up a sceptical position with regard to the alchemistic problem ; he considered the evidence adduced in favour of the ennobling of metals as insufficient, notwith- standing that his famous teacher Sylvius had given himself up unreservedly to the belief in their transmutation.
The power of this belief was still so great at that time,, when the phlogistic period was just beginning and chemistry was striving to develop itself independently, that it took firm root in the minds of even the most discerning men, with Boyle at their head. The latter was firmly convinced of the possibility of transmuting individual metals into one another, as were also many of his contemporaries and successors, e.g. Glauber, Homberg, Kunkel, Stahl and Boer- have, of whose earnest desire to arrive at the truth there can be no doubt whatever. That the wished-for goal was never reached, in spite of the most unwearied efforts, did not shake their belief in the correctness of the assumptions of alchemy; Stahl alone began to doubt these towards the end of his life, and warned his brethren against alchemistic frauds. The vitality of the belief in transmutation depended chiefly on the theoretical opinions which these men held re- garding the composition of metals ; the primal error of the pseudo-Geber and his disciples was thus propagated for centuries through the alchemistic age.
Bo'erhave was the last distinguished chemist to support with his great authority some of the alchemistic views, while he foiled to criticise others of the fraudulent asser- 'tions with sufficient sharpness. After his time no notable exponent of chemistry — which had now attained to the rank of a science — spoke in their favour; but all the greater was the number of cheats and swindlers who culti- vated the lucrative field of gold-making even during the
tf4 THE AGE OF ALCHEMY CHAP
eighteenth century. The conviction of the impossibility of transmutation, which was at that time establishing itself among scientific chemists, made its way but slowly into •outer circles. Credulity, and the hope of obtaining riches for nothing, were the means of leading many into very •doubtful paths, even so late as the end of the eighteenth •century and the beginning of the nineteenth.1 The final echoes of the alchemistic problem, which had for so long a period of time held the cultured of every nation . in a state of tension, and had even blinded eminent scientific men, only appear to die away during the last decades of the nineteenth <jentury.
Seeing the marvellous results which alchemy produced, it is but natural to inquire more closely into the supposed evidence in favour of the ennobling of metals, and to ask what kind of observations led to this being regarded as a matter of fact. If most weight is to be laid upon the statements of men who had established their claim as practised observers, then first place must be given to the records of the great physician and chemist, van Helmont (towards the middle of the seventeenth century), respecting transmutation as carried out by himself; these records afford the most remarkable testimony to the power of alchem- istic illusions. Van Helmont had received from an unknown •source a small specimen of the philosopher's stone, and with this he states that he transformed several portions of mer- cury into pure gold, giving the exact proportions by weight ; one part of this preparation sufficed to transmute 2000 parts of mercury.
Soon after the death of van Helmont, Helvetius, body- physician to the Prince of Orange, published a detailed account of the transmutation of lead into gold, by means of a trifling quantity of a preparation which had come to him from the hand of a stranger. It appeared impossible to
1 For details on these points, especially for an account of the interesting relations of the Rosicrucians to alchemy, aiid of secret alohemistio associa- tions, etc., see H. Kopp's Die Alchemie in alter er und neuer&r Zeit, a book which gives us a clear insight into the workings of the alchemists.
ii ALCHEMY AT THE GERMAN COURTS 66
doubt the testimony of such men, who were held in high esteem by all the scientific investigators of that time.
More palpable proof of the actual transmutation of metals was held to be furnished by the coins or ornaments prepared from alchemistic gold up to and in the eighteenth century. l The evidence, which came for the most part too late, that these consisted of worthless alloys (e.g. bronze gilt over), was all too soon forgotten. The findings of courts of justice, too, in favour of alchemistic operations, were looked upon as proofs of transmutation having been actually accomplished.
As has been already mentioned, a large number of •German princes gave unremitting support to the efforts of the alchemists, being induced to do so by the hope of large gains. Many of them worked zealously at transmutation themselves, among others John, Burgrave of Nurnberg, who received the surname of " the Alchemist " ; the Emperor Rudolph II., the most powerful protector of the makers of gold; the Elector Augustus of Saxony, the Elector John George of Brandenburg, &c., &c. The courts of these princes were the field-grounds of adepts, who for long succeeded, by means of clever experiments, in maintaining .a belief in their art among these Maecenases, until, as usually happened, they were unmasked as cheats and generally severely punished, after having been the cause of excessive expenditure on the part of their patrons.
It is impossible to enter here into details of the romantic lives of alchemists like Leonhard Thurneysser, physician at the court of John George of Brandenburg, Sendivogius, Caetano (on whom the title of Count was bestowed), St. Germain, Cagliostro, &c. The two last named lived at a time when chemistry was strong enough as a science to protect itself against the frauds of alchemy. The opposition to the latter which was raised in the course of the preceding century by chemists of repute, e.g. Geoffroy the elder (the earlier warnings of Erasmus of Rotterdam, Athanasius Kircher, Leonardo da Vinci 2 and Palissy having
1 Of . E. Kopp's Alchemie, vol. i. p. 90, et aeq.
a Leonardo da Vinci, the gifted physicist and artist, a man versed in
F
66 THE AGE OF ALCHEMY CHAP
had no effect), led to its ultimate fall, which even the amalgamation of alchemistic aims with those of the secret societies (Rosicrucians, Illuminates, &c.) was powerless to retard. The belief in the possibility of the transmutation of metals received its actual deathblow from the new chemistry which began with Lavoisier.1 At the same time, however (i.e. about the year 1790), the Hermetic Society endeavoured to foster and maintain the alchemistic illusion in Germany. It has only recently come to light that the leaders of this undertaking were Kortum (the poet-author of the Jolisiade and a practising physician in Bochum, Westphalia) and a. Dr. Bahrens, a clergyman. But Wiegleb, a chemist and pharmacist of merit, combated those belated efforts with entire success (cf. E. Schulae's work, Die Hermetische Gesellschaft. Leipzig, 1897).
The melancholy errors which arose from the introduction of the mystical religious element into alchemy can but be indicated here ; the assertion frequently made by adepts, that the secret of making gold was revealed t6 them through the grace of God, only excites feelings of repugnance.2
almost every branch of the science of his day, spoke of alchemy OB a false and ruinous calling, and declared that the artificial production of gold was as impossible of achievement as the discovery of perpetual motion (cf. B. 0. von Lippmann, Ztschr. flir Naturwissenachaften, 1899, p. 291). In his Codex Atlaitticua L. da Vinci says:— "The deceitful interpretera of nature assume quicksilver to be the common germ of all the metals, forgetting that nature varies its seeds according to the different things which those seeds are meant to bring forth." Compare the erudite work of M. Herzfeld: — Leonardo da Vinci, der Denker und Poet (Leipzig, Eug Diederichs, 1904).
1 Schmieder, who published a history of alchemy in 1832 (in Halle), did not hesitate to accept the transmutation of metals as having been actually accomplished by various adepts. He expresses himself with more caution regarding the assumed efficacy of the philosopher's stone as a medicine and a means of prolonging life. Even in quite recent times we find the study of alchemy carried on, ostensibly with result, e.g. in Paris in 1844 (cf Bftudrimont, Traite de Ghimie, vol. i.).
a Had such misuse of the name of God and of the Bible been made in the time of Luther, as was later the case, or had he been aware of it hia opinion of alchemy would have been a much lower one ; as a matter of fact he valued it because of its bearing upon religious feeling. In contradis- tinction to this stands Melanchthon's criticism of alchemy, a criticism
i GENERAL EFFECT OF ALCHEMY ON CHEMISTRY 67
Other frauds, which were likewise the products of alchemistic effort during the eighteenth century, to go no further back, merely provoke satire ; among these may be mentioned the endeavours to prepare from the air the so-called " substance of shooting stars " (the alga Nostoc commune, which is found in wet ground, was so regarded), and the materia yrima from " air-salt."
The real benefits which have accrued to chemistry during the last four centuries from the mania for pro- ducing gold from the base metals, can only be estimated as very slight. It was but seldom that a discovery of technical importance, like that of the making of porcelain by Bbttger,1 sprang from alchemistic work. On the other hand, it did a vast amount of harm during that period, for it crippled the usefulness of many able men who would undoubtedly have advanced science, had they not been influenced by chimeras of an exciting nature ; as it was, they were led away into the most tortuous paths.
We are thus forced to the above unfavourable criticism of the work of the alchemists on their problem of the trans- mutation of metals, in spite of the striking and seemingly incontestable evidence in favour of the latter ; in spite, also, of a strong inclination at the present time to a belief in the mutual convertibility of elements chemically similar — a be- lief grounded upon speculations with regard to a primary material which do not seem to be without foundation. But in no single case, as yet, not even in the very recent researches of Fittica (see Special History), has there been any positive evidence brought forward in support of this idea.
If, therefore, we review the work of the alehemisbs during
which testifies to the sobriety of his judgment (he called it impoaliirum guandam sophisticam).
1 Johann Friedrich Bottiger was born at Sohleiz, Thuringia, in 1685, and died at Meissen in 1719. The adventurous career of this remarkable man is pourtrayed clearly and minutely in a work written by Bruno Wolff-Beckh (Berlin, 1903), which also contains a bibliography of the litera- ture upon Bb'ttiger. The name is written BSttiger in the parish register of Sohleiz, but he himself usually signed BSttger.
F 2
THE AGE OF ALCHEMY OH. n
the last fifteen centuries, we arrive at the conclusion that it was based upon a series of falsely interpreted chemical problems. The expectation of the easy acquirement oi boundless riches, the auri sacra fames to which it led, formed the powerful stimulus to the useless, and yet continually renewed, efforts of an unsatisfied mankind.
CHAPTER III HISTORY OF THE IATRO-CHEMICAL PERIOD
INTRODUCTION. — Traditional belief, which dominated every branch of science during the Middle Ages, exercised its power not least in the domain of alchemy, for almost every one engaged in chemical pursuits was deluded by the idea that gold and other bodies could be artificially prepared. In the course of the fifteenth century, however, this yoke, which had hindered the development of free inquiry, was in many quarters cast off. The sciences.,, hitherto studied almost alone in the cloister, now found a. foothold in the universities of Italy, France, England, Ger- many and other countries, which were then both increasing^ in number and expanding rapidly ; the free interchange of ideas among these seats of learning rendered a development of the sciences possible, as it had never been before. That the discovery and spread of the art of printing contributed materially to this, hardly requires to be stated ; for new ideas, which were opposed to those prevalent up till then, and which had hitherto been restricted to a narrow circle, became quickly disseminated by its aid. Any one could inform himself as to the range of any particular science by means of the encyclopedias and special memoirs which were being printed in increasing numbers. As a consequence of this, the capacity for independent criticism spread, one of the most effectual of remedies against the domination of the scholastics being thereby created. A farther aid tq controverting scholastic principles was found in the in-
70 THE IATRO-CHEMIOAL PERIOD OHAP.
ductive method, then gradually forcing itself forward, by means of which the experimental sciences were called into life.
In addition to these impulses of a freer spirit, chemistry received a powerful impetus from the increase in scientific knowledge which resulted from the .discovery of the New World and of the ocean route to the East Indies. All these events testified to the birth of a new era, which found its moat powerful expression in the works of the Reforina- tion.
At that time chemistry strove to free itself from the exclusive domination of the alchemistic idea. And even although the latter was not totally supplanted, another aim came into prominence, an aim to which a scientific character could not be denied ; the chemical knowledge of that day was, however, so very imperfect, that a solution of this new problem was not to be expected. Chemistry was, in fact, to be intimately conjoined with medicine ; each (so many opined) was to help the other. The chemist was to discover the medicines, prepare them carefully, and investi- gate them chemically, while the physician was to examine and explain their action ; or, better still, both things were to be united in one person. The mutual interaction of chemistry and medicine is the main idea which runs through the iatro- chemical age, and which gives to the latter its own particular stamp.
What benefit, then, accrued to both of them from this ? The answer is, a mutual enrichment, which did almost more for chemistry than for medicine ; for the former was raised to a higher level through being transferred from the hands of laboratory workers, who were mostly uneducated, to those of men belonging to a learned profession and possessing a high degree of scientific culture. The iatro-chemical age thus formed an important period of preparation for chemistry, a period during which the latter so extended her province that she was enabled in the middle of the seventeenth century to stand forth as a young science by the side of her elder sister physics. That period was for chemistry an apprenticeship in
in LIFE AND WORK OF PARACELSUS 71
the fullest sense of the word, during which she laboriously acquired the capacity to see that the iatro-chemical doctrines were untenable, and to apply herself to her true vocation.
GENERAL HISTORY OF THE IATRO-OHEMIOAL PERIOD AND PARTICULARLY OF ITS THEORETICAL VIEWS.1
The main, currents of the iatro-chemical age emanated from Paracelsus, van Helmont and de le Boe Sylvius, wibh whose name must be coupled that of his most distinguished pupil, Tachenius, their doctrines being spread by schools of greater or lesser importance. Besides these there were some men who worked independently, or who at least did not entirely subordinate themselves to their authority, of whom Libavius, Glauber and Sala may be mentioned. Other men like Agricola, Palissy, &c., employed their energies, also independently, in a totally different direction, giving all their attention to technical chemistry.
Paracelsus and his School.8 — Paracelsus was the man who, in the first half of the sixteenth century, opened out new paths for chemistry and medicine by joining them together. To him is undoubtedly due the merit of freeing chemistry from the restrictive fetters of alchemy, by a clear definition of scientific aims. He taught that " the object
1 Of. Kopp, Geachichte der Chemie, vol. i. p. 84.
'- The recent researches upon Paracelsus — more especially Fr. Mook's Theophrastua Paracelsus (Wurzburg, 1876) ; E. Schubert and K. SudhofFs Paracelmia-fforschungen (Frankfurt, 1387-9) ; and Aberle's Gfrobdenkmol, ScMdel und Abbildungen des Tlieophrostus Paracelsus, dbc. (Salzburg, 1891) (" The Gravestone, Skull, and Portraits of Theophraatus Paracelsus, &o.") — have thrown nmoh light upon the life and work of this truly eccentric man. They materially enhance oar appreciation of the real services which he rendered. Franz Strunz, too, has still more recently helped further towards a right understanding of Paracelsus by a characteristically written biography, full of life, and at the same time both searching and sym- pathetic. He has likewise begun the publication of Paracelsus' more important works with a carefully edited issue of the book Paragranum, and with an annotated edition of the compendious work Paramirum I. and II. (Diederioh, Leipzig, 1903).
72 THE 1ATRO-OHEMICAL PERIOD OHAP.
of chemistry is not to make gold but to prepare medicines." True, chemical remedies had "been used now and again before his time, but Paracelsus differed from his predecessors in the theoretical motives which led him to employ them. He regarded the healthy human body as a combination of certain chemical matters ; when these underwent change in any way, illnesses resulted, and the latter could therefore only be cured by means of chemical medicines. The foregoing sentence contains the quintessence of Paracelsus' doctrine ; the principles of the old school of Galen were quite in- compatible with it, these having — indeed — had nothing to do with chemistry.
Paracelsus entered the lists with great boldness, and with a marvellous vigour, to combat the old doctrines long accepted by all physicians. However little one may agree with his exaggerations now, he effectually obviated by his action the growing stagnation of medicine, and partly carried through valuable innovations, partly incited others to do so.
His career was not calculated to raise him in the esteem of his opponents, that is, of nearly all the physicians of the time. Paracelsus (his full name was Philippus Aureolus Paracelsus Theophrastus Bombastus von Hohenheim *) was born at Einsiedeln in Switzerland on November 10th, 1493, and returned to his native country about 1526 as a physician celebrated for his wonderful cures, after an extremely unsettled life and the most romantic wanderings in almost every country in Europe. The chair of Medical Science (therapeutics) at Basle was conferred upon him, and this position, together with his fame as a doctor, he made use of to spread the iatro-chemical doctrine, and to fight against the old medical school with every possible dialectic weapon. He discredited the hitherto undisputed authority of Galen and Avicenna, and succeeded by means of popular lectures given in German, as well as by his rude originality in teaching and conversation, in gaining a large number of adherents. A quarrel with the Basle Municipal Council soon compelled
1 The other names given to him are not historic. It should be noted that Paracelsus came of the old Suabian family of Bombastus.
in THE SYSTEM AND VIEWS OF PARACELSUS 73
him, however, to leave that town (in 1527), and after moving about restlessly in Alsace, Bavaria, Austria and Switzerland, he at last came to Salzburg in the Tyrol, where he died on September 24th, 1541, in wretched circumstances. The assertion that Paracelsus was done to death by the hirelings of physicians who were his enemies, has been proved to be unfounded (cf. Aberle, loc. tit.').
There has at all times been much difference of opinion in criticising this gifted man, whose life offered such a contrast to his mental capacity. Bated too high, and even extolled by his disciples,1 and also by many who disapproved of his doctrines, he was, on the other hand, too much dis- paraged by his opponents and by chemists who criticised him as historians. 'The cause of this — for the most part — depreciatory criticism has only recently come to light through the historical researches already mentioned (p. 71, note 2). These have shown that much of the subject matter in the works attributed to Paracelsus, which had often caused a distorted view to be taken of the man, was not really his. The good to which he incited by his reform- ing labours seldom found the recognition it deserved, from its being so much mixed up with charlatanism and coarseness, while the overweening estimation in which he held himself may have helped to make him ridiculous in the eyes of thoughtful physicians. On the other hand, if we are to judge by his will and testament, Paracelsus appears a noble and upright man, a humane physician whose chief aim was " to restore to health this poor, suffering and needy race " ; or, as he also otherwise puts it, "the main foundation .of medicine is love." At the same time (as Strunz especially emphasises) he was a Christian humanist who cherished the hope of leading mankind gently to the " Kingdom of God " by inspiring- them with a love of conscientiousness and veracity. Thexe can, at all events, be no dispute as to his deserving the title of a "man of rare originality," which
1 Of. A. N. Selierer's memoir Theophrastus Paracelsus (St. Petersburg, 1821). Francis Bacon criticised him more reasonably, praising his endeav- ours to arrive at the truth through the light of experience.
74. THE IATRO-CHEMICAL PERIOD OHAP.
was bestowed upon him, by his contemporary Sebastian Franck.
At the root of his iatro-chemical doctrines, which he imagined were based upon ample experience, lay the idea already mentioned — that the operations which go on in the human body are chemical ones, and that the state of health depends upon the composition of the organs and the juices. With respect to the constituents of organic bodies, Paracelsus adhered to the old assumption that the latter were composed of the three substance-forming qualities (elements) mercury (mercurius), sulphur and salt. Indeed in spite of many contradictions in the details of his theoretical views, this hypothesis forms the foundation of his whole system.1 These three principles correspond to the physical "phenomena of volatilisation ( Verfluchtbarkeit}, combustibility (Oligkeit} and solidification (Festigk&ity Mercury, sulphur and salt, from which human beings (the microcosmos) are built up, are in a higher sense related to spirit (JSigenschaft), soul (Staff), body (Gestalf) and, finally, to the world as a whole (the macrocosmos). This generalisation is entirely characteristic of the natural philosophy of the Renaissance period.
When one of these elements predominates, or when it falls below its normal amount, illnesses ensue. This idea is expressed in the most fantastic manner in the writings of this strange man, as the following sentences show:— An increase of the sulphur gives rise to fever and the plague, an increase of mercury to paralysis and depression, and an increase of salt to diarrhosa and dropsy. By the elimina- tion of the sulphur, gout results, and by distilling it from one organ into another, delirium, and so on. — However un- founded such opinions are, it is possible to find a certain sense in them.
He designates tartwus as the cause of various illnesses, meaning by this expression precipitates from juices which in
1 Medicine rests, according to the remarkable statement of Paracelsus, upon four pillars, of whioh chemistry forms one ; the three qthers are philosophy, astronomy and virtue.
in PARACELSUS' VIEWS UPON DISEASES 76
the healthy state contain no solid particles. The deposition of concretionary matter, which he may have observed in the affected organs during many diseases (such as gout, stone in the kidneys and gall-stones), no doubt led him to this partially sound conclusion. The comparison of such secretions with known sediments, particularly with tartar, led to the general designation tartarus ; the word had possibly also a double meaning, recalling the severe pains which people afflicted with these ailments had to endure.
While Paracelsus endeavoured in this semi-rational, if also fantastic, manner to reduce pathological processes to chemical causes, he assumed nevertheless for his iatro- chemical doctrine the action of particular forces in certain cases, which forces he, in his rough, realistic manner, pictured to himself as personified. Digestion, in especial, was regulated by the action of Archeus, who — as a good genius — rendered the nutriment consumed digestible, effected the separation of indigestible matters and provided generally for the preservation of a proper equilibrium. Diseases in the stomach were produced by Archeus becoming ill. In this interpretation of such a specific chemical process as digestion, Paracelsus was disloyal to his own principles. It fell to the later iatro-chemists to clear their doctrinal system of this incongruity.
Diseases were to be cured by medicines (arcana), the preparation of which, as we have already seen, was — according to Paracelsus — the aim of chemistry. Due recognition must be given here to the fact that this axiom infused new life into the effete medical doctrines. Paracelsus enriched medicine with a large number of valuable preparations. The manner in which he applied most of these must remain unknown to us ; but it is certain that he effected numerous brilliant cures in cases of serious illness. With regard to the preparations which he employed, we know that he was the first to make use of lapis infernalis, copper vitriol, corrosive sublimate, sugar of lead, and various antimony compounds as medicines, these metallic compounds having hitherto been looked upon with dread, on account of
76 THE IATRO-CHEMIOAL PERIOD CHAP.
their poisonous properties. Further, he brought into use dilute sulphuric acid, " sweetened oil of vitriol " (sweetened by spirit of wine, and which was known at a later date as- Haller's acid), tinctures of iron and iron saffron ; and he also introduced better methods for preparing and utilising various essences and extracts. He appears to have attained great success by the judicious prescription of laudanum.
That Paracelsus gave a tremendous impetus to the higher development of the apothecary's calling by such generous additions to the medical treasury goes without saying ; for, before his time apothecaries' shops were nothing more than stores for roots, herbs, syrups, and confections of every kind, the preparation of the latter being carried out . exclusively in them. The making of new medicines presupposed an acquaintance with chemical facts and processes ; pharmacists had therefore to be continually striving to attain to this knowledge, pharmacy, in the proper sense of the word, taking its beginning here. The service which Paracelsus rendered in instigating physicians and apothecaries to busy themselves with chemistry was a very great one, but Scherer goes too far when he says that " pharmacy owes everything to Paracelsus." 1
The trenchant innovations which Paracelsus strove to introduce gave rise to violent agitations among his contem- poraries, agitations which were continually receiving new food from his numerous memoirs, circulated in various languages, and dating for the most part from the time after his departure from Basle. These gave frequent opportunity for vehement contradictions on the part of the old medical school. So far as their composition goes, and more especially as regards their style, his writings are of surprising origin- ality, while they reflect at the same time the unsettled life of the author. They show great self-consciousness, but on the other hand prove that he was free from hyprocrisy and full of humble adoration of whatever was Divine and genuine. Through them all he points in vigorous language to the ex- perience gained by experiment,— to the " light of nature."
1 Loc. cit.
in SERVICES RENDERED BY PARACELSUS 77
One frequently comes across a breath of true German nature- poetry in them.
His chemical knowledge and his views with regard to the origin of diseases are best seen in the following works : — Archidoxa ; De Tinctura Physicorum ; De morbis ess Tartaro Oriundis ; Paragranuin ; Paramirwn (I and II) ; Gfrosse Wwndarznei.
The results of the labours of Paracelsus were not long in manifesting themselves. Hia pupils, inspired by the new doctrines, glorified him as the reformer of medicine; while the adherents of the old school, on the other hand, resisted desperately the innovations and attacks which undermined their views. A violent contest ensued and continued for a long time, until it was decided, if not al- together in favour of Paracelsus, at least in that of the more moderate iatro-chemists. It does not lie within the scope of this work to enter minutely into these controversies, sufficing as it does to indicate here the significance of the new medico-chemical views for the development of chemistry. But we may mention that the Swiss physician Erastus (whose German name was Lieber), who remained faithful to the doctrines of Galen, was Paracelsus' chief opponent, and was especially instrumental in exposing the contra- dictions which were contained in his later writings. The medical world was agitated during the sixteenth century by the polemical writings on both sides. Of the disciples of Paracelsus, who, less gifted than their master, reproduced his ideas and imitated his less amiable peculiarities, especially his charlatanism, but who fell short of him as scientists, Leonhard Thurneysser 1 (called zum Thurm) was the best known. The latter achieved nothing of any note for chemistry, but his unsuccessful appearance as an adept ensures for him a place in the history of alchemy (of. p. 65).
1 A good account of Thurneyaaer's performances is to be found in Moehsen's admirable work, Heitrage zur Geschichte derWiasenachafieninder Mark Brandenburg, c&c. (Berlin and Leipzig, 1783). Cf. also A. W. Hof- mann'g admirable lecture, Berliner Alchemisten und Ohemiker (1882).
THE IATRO-OHEMICAL PERIOD
The acts of men of this calibre, who wrought immense mischief by the reckless use of poisonous preparations, render intelligible the attempts which were made to put a stop to their excesses by legal statute. This is seen, for instance, by the parliament of Paris prohibiting the prescription of antimonial preparations, and by the sentenco of condemnation which the medical faculty of Paris hurled against every attempted innovation in the healing art.
But, in a wider sense, there belonged also to the school of Paracelsus men of scientific eminence who did not subscribe to all his doctrines, but rather regarded them from a critical point of view, and who endeavoured in a rational manner to extract the good which they contained. The most pro- minent of these physicians and chemists at the end of tho sixteenth and beginning of the seventeenth centuries were Turquet de Mayerne and Libavius, Oswald Oroll and Adrian van Mynsicht. These were for some time contemporaries of van Helmont, and formed the connecting link between Paracelsus and that remarkable man. They greatly enriched, not only medicine, but also chemistry.
.Turquet de Mayeme was born at Geneva in 1573, and became a noted physician in Paris. Holding, however,' as he did, that the antimonial preparations now in ill- repute were necessary, and therefore proscribing them, he found it impossible to keep on good terms with his professional brethren in that city, and preferred to become body-physician to the King of England, in which country he died in 1656. His knowledge of chemistry was very highly developed for that age, as a consequence of which he laboured earnestly for the rational application of chemical remedies, without falling into the exaggerations of Paracelsus on the one hand or rejecting all the medicines of the school of Galen on the other.
The physicians Croll and van Mynsicht busied them- selves in a similar manner and at about the same time Having a good knowledge of chemistry, they brought into vogue many of the medicaments of Paracelsus, together with other new preparations; among the latter, Croll was the
LIBAV1US 79
first to recommend the use of sulphate of potash and of volatile salt of amber (succinic acid), and van Mynsicht that of tartar emetic.
Andreas Libavius (Libau), born in Halle, attracts our attention in a high degree by the critical position which he took up with regard to many of the errors of the school of Paracelsus, and especially also by many new observations which he contributed to chemistry. He was the first chemist of note in Germany who stood up manfully against the excesses of Paracelsus, and who vigorously combated the defects in his doctrines, the obscurities in his writings, his phantasies and sophisms, and the employment of "secret remedies." Originally a physician, Libavius attained to a wide knowledge of chemistry, which he helped to extend, although latterly he devoted himself chiefly to historical and philological studies. He died in 1616 as director of the gymnasium at Coburg, having previously worked with great success as a physician and, at the same time, as head of the " Latin School " at Rothenburg on the Tauber from 1591 to 1607. Thanks to his medical knowledge and to his thorough general education, Libavius was able to appreciate better than his contemporaries the influence which chemistry ought to exercise upon medicine ; he took up a position midway between those of Paracelsus and his opponents, the latter of whom wished nothing less than to banish chemistry from medical science. Notwithstanding his sound judgment, however, of which he gave many proofs, he could not quite free himself from the predilection of his time towards alchemy.
Libavius did chemistry a real service in writing his' text-book, which was published in 1595 under the title Alclvymia, and which contained all the most important facts and theories germane to the subject at that date. His other writings, in which he combated the weak points of the Paracelsian school (as indicated above), and also described new chemical observations, appeared in three volumes shortly before his death, under the title Opera Omnia Medico-ckymica. We shall still have frequent
80 THE IATRO-CHEMICAL PERIOD OHAP.
occasion to refer to his practical chemical knowledge, which was attested by the discovery of important facts.
It is worthy of note that Libavius made a vigorous effort to establish chemical laboratories, in which scientific work should be carried out. From the proposals which he brought forward with this end in view, it is evident that he was desirous to provide plenty of accommodation in these laboratories, and to furnish them with fittings of the most varied kind.1
Joliann Baptist van Helmont and his Oontempwaries.
A distinguished place and a detailed notice in the history of the iatro-chemical period is due to van Helmont,- one of the most eminent and independent chemists of his time. Endowed with rich acquirements and experiences in medicine and chemistry, he surpassed those of his con- temporaries who laboured in the same field. His life was for the most part that of a scholar working in quiet, although his brilliant outward circumstances (he belonged to a noble Brabantine family) seemed hardly in keeping with this. Born in Brussels in the year 1577, he applied him- self at an unusually early age to the study of philosophy and theology; but finding no satisfaction in these, he renounced them to devote himself to medicine. At first an adherent of the old school of the Galenites, he soon recognised its deficiencies, and turned to the doctrines of Paracelsus, accepting them, however, only in part. With a growing enthusiasm for his physician's calling, he fought against the old medical system, and materially contributed by his brilliant services in bringing about its fall. Without
1 For an account of the life and work of Libavius, of. Ottmann's lecture in the Verhandlungen der Qesellachajl Deutacher Naturforscher, <&c., 1804, vol. ii. p. 79.
3 Details of van Helmont's life and teaching are to be found in a recent publication by F. Strunz (cf. Ohem. Zeitung for 1902, Nos. 77 and 78 ; MoncU/the/le der Comenius Gesellschqfi, vol. x. , Noa. 9 and 10 ; Janus for 1903, NOB. 2 and 3).
in VAN HELMONT'S LIFE AND WORK 81
van Helmont, iatro-chemistry would never have attained to the height to which it was subsequently raised by Sylvius and Tachenius. In addition, he enriched pure chemistry by a very great number of valuable observations. So attached did he become to his scientific pursuits that he declined the tempting offers of princes, preferring to investigate the secrets of nature in his laboratory at Brussels, in which city he died in 1644.
In van Helmont wonderful contradictions were united. In contrast with his gift of sharp and temperate observation, there was an intense inclination towards the supernatural — possibly the result of his mystical and magical studies, to which, as well as to theology, he had applied himself. Thus, this same man, who laid the foundation of the first exact knowledge of gasea, and who showed thereby a keenness of perception unapproached before his time by any other ob- server, defended the transmutation of the base metals into gold with the utmost vigour (cf. p. 64) ; his belief in this was grounded so finnly that illusions arose from it which are to us incomprehensible.
After this it is easy to understand that van Helmont was not free from fantastic ideas of a less questionable nature. His theoretical views upon the elements and his iatro-chemical doctrines yield many proofs of this ; but, on the other hand, much of his knowledge was so sound, and he was able to expound it so much better than any of his predecessors, that the good service which he rendered far outweighed the bad effect of any of his mistakes.
Van Helmont had his own opinion with regard to the primary substances of which matter was composed; he neither accepted all the four Aristotelian elements1 nor those which were assumed by Basil Valentine, but looked upon water as the chief constituent of all matter. That it was present in organic bodies he concluded from the fact of
1 With reapeot to air, it is uncertain whether van Helmont looked upon it as an element or not. He denied altogether that fire could be of a material nature, which is evidence of his extraordinary clearness of per- • Oeption.
G
82 THE lATRO-OHE^nCAL PERIOD CHAP.
invariably finding it as a product of their combustion. He imagined that he contributed a strong- proof of this by an experiment which showed that plants could be made to grow luxuriantly in pure water alone, which, he believed, was their only nutriment under the circumstances. That he was thereby convinced of the transformation of water into earthy matter is therefore quite intelligible.
Whilst van Helmont thus subscribed to the same error that held possession of many minds both before and after his time, he nevertheless recognised much more clearly than his contemporaries the unchangeableness of matter in numerous: instances; thus he contributed more than any one else to do away with the belief that the copper thrown down from a solution of copper vitriol by means of iron was newly created. He further showed that the same substance con- tinued to exist in many of its compounds, e.g. silver in its salts and silica in water glass, the latter yielding, on decomposition with acids (according to his own memorable observations), the same amount of silicic acid as was originally used to prepare it. These were views and observations of the greatest moment ; for, in place of the former obscure conceptions as to the formation of chemical compounds, he substituted the doctrine that the original substance, even after undergoing chemical changes, remains present in the new products. He had therefore clearly grasped the fundamental idea of the conservation of matter in particular cases.
Van Helmont thus stands out as unique in those ideas, which pointed out new paths to chemistry. The relations between chemistry and medicine, too, the latter of which he also ardently fostered, led him to views which likewise possess a partial originality, since he endeavoured to decide theoretical questions by means of experiments with juices and other secretions of the animal body. The reactions which go on in the liquids of the body were in, his opinion of especial importance, for, according as the latter were acid or neutral, they regulated its most important functions. Besides the chemical nature of the juices, fermentation was, according
in VAN HELMONT'S CHEMICAL KNOWLEDGE 83
to him, the principal cause of the organic processes ; but he expresses himself less clearly upon this point than upon the significance of the chemical reactions. Indeed, he could not quite free himself from the idea of Archeus governing diges- tion and the processes connected with it. On. the other hand, he stood on solid ground in his explanation of vital processes, when he took into account the chemical nature of the juices. He held that the acid of . the gastric juice brought about digestion, but this, if present in excess, gave rise to discomfort and illnesses, which were the more serious the more acid there was ; and the latter could not then, as under normal conditions, be neutralised by the alkali of the bile, which mixes with the gastric juice in the duodenum. To cure any of the ailments produced in this way, van Helmont declared that medicines of an alkaline nature (alkaline salts) must be used ; while those of an opposite kind, which arose from a deficiency of acid, were to be treated by medicines of an acid nature. He also recom- mended the latter in cases of gout, stone and similar diseases, which likewise originated (in his opinion) from an insufficient or irregular admixture of the juices. These views show a distinct advance upon those of Paracelsus. For, while the latter assumed the presence of arbitrary constituents — in-, capable of preparation — in organic matter, van Helmont searched for the actual substances themselves, and compared the interactions of the various juices which mingle with one another with similar reactions of solutions outside the organs* — a procedure which laid the first foundation, however insecure, of chemical physiology.
Van Helmont proved himself an original investigator of the first rank, who opened out new ground for chemical science by his researches on gases — researches which con- stitute him the real founder of pneumatic chemistry, though this indeed only attained to a considerable devejppment a century after his time, when the discoveries connected with it brought about the great reform of the science. If we consider that before van Helmont's time the most various gases, such as hydrogen, carbonic acid and sulphurous , acid,
Q 2
84 THE IATRO-CHEMIOAL PERIOD CHAP.
were looked upon as not differing materially from ordinary air, and that he was the first to characterise gaseous sub- stances as different, by investigating their properties, we gain some idea of the immense services which he rendered. He it was who gave to them the generic name of " gas," l and he further distinguished them from vapours, in so far that the latter were condensed to liquids upon cooling, while the former were not.
Van Helmont specially examined carbonic acid and showed how it was produced from limestone or potashes with acids, from burning coal, and in the fermentation of wine and beer ; he also pointed out its presence in the stomach, and its occurrence in mineral waters and in many natural cavities in -the earth. He usually termed it gas sylvestre? To the want of suitable apparatus for collecting gases are to be ascribed the imperfections in many of his observations, and also the confounding of carbonic acid with other gases which were non-supporters of combustion like itself; nevertheless he described the two combustible gases — hydrogen and marsh gas — as peculiar varieties of air. His collected works were published in 1648 by his son under the title, Ortus Medicince vel Opera et Opiiscula Omnia.
Van Helmont's influence upon his contemporaries and upon the development of the iatro-chemical doctrines must be rated very high. By his introduction of chemical ideas into medical science, the latter was advanced, because the use of chemical medicines seemed natural from thence- forth; moreover, in his Pkarmacopolium ac Dispensatorium Modernum, he published suitable prescriptions for the pre- paration of medicines. The scientific spirit which he endeavoured to introduce into the healing art tended to
1 In choosing this designation, van Helmont says that he had Chaos in hie mind. Whether he was also influenced here by the process of fermenta- tion (the Dutch word for the verb " to ferment " is gisten), as is contended by others, appears doubtful.
8 By the designation sytvestre, he doubtless meant to indicate the im- possibility of condensing the gas ; at least he says in one passage : Gau syhestn, aive incSercibile, quod in corpus cogi non potest visibile.
m ANGJSLUS SALA; DANIEL SENNERT 85
its more healthy development, in contrast with the em- piricism of the Paracelsian school. As an acute psychologist, too, van Helmont deserves recognition.1
In a similar manner, if in lesser degree, various other physicians of that time were also active. Well equipped with chemical knowledge, they pursued the practice of their calling, and were enabled by their clearness of vision to re- cognise and combat many evils, e.g. those which arose from the use of secret remedies ; among them we must mention Angelus Sala and Daniel Sennert. 'Sala,2 who practised as body-physician at the Mecklenburg Court in the first half of the seventeenth century, awakens our surprise by his able criti- cisms both of the Paracelsian and of1 the old medical schools, and also by his (for that time) wide knowledge of chemistry. This knowledge, conjoined with his solid medical experience, was of the utmost value not only to pharmacy but also to pure chemistry ; for he formed correct ideas with regard to the composition and reactions of many chemical compounds, such as had never been advanced before his time. Thus he tells us that salmiac consists of hydrochloric acid and car- bonate of ammonia (flucktiges JLaugensalz), and he also knew that sulphuric acid was able to drive out nitric acid from its salts, &c.
Sennert, who taught as professor at Wittenberg in the first quarter of the seventeenth century, devoted his energies chiefly to proving to the medical world the wonderful efficacy of chemical remedies, when these were properly applied. It is true that he was never able to disentangle himself from many of the erroneous conceptions of Paracelsus, for instance, from the doctrine of the three primary elements ; but he worked effectively against the serious abuses which had crept into medicine as the result of these, especially against the so-called universal remedies.
1 Cf. the paper on van Helmont' s psychology by OFr. Strnnz in the Bericht der 76- Veraammlung deutacher Noturforscher und A&rzte (Cassel).
2 Angelo Sala was born at Vicenza in 1576 and died in 1637. His relations with chemistry, medicine, and alchemy are minutely detailed in a work by Alph. Cossa, Angelo Sala Medico e Chimico Vicentino del Secolo
, 1894).
86 THE IATRO-OHEMIOAL PERIOD OHAP.
Sylvius and Tachenius.: — F. de le JBoe (Dubois) Sylvius was born at Hanau in 1614, and, after a thorough grounding in scientific and medical studies, practised with great success as a physician, and later on, until his death in 1672, was famous as professor of medical science in Leyden. In his knowledge of medicine he far surpassed most of his contemporaries. He was aware of the difference between arterial and venous blood, and ascribed the red colour of the former to the air absorbed in breathing. Combustion and respiration were in his view precisely similar phenomena. He directed all his efforts, as instanced in this latter case, to proving that the processes which go on in the human body — whether they be normal or pathological — were purely chemical ones. The spiritualistic element which was mingled with the doctrines of Paracelsus and van Helmont was to be entirely set aside. Digestion, for instance, which only appeared possible to the two latter by the intervention of a spirit (Archeus), was regarded by Sylvius as a chemical process in which the saliva primarily, but also the gastric and pancreatic juices and the bile, were the most important acting agents. To the acid, alkaline, or neutral reactions of the juices of the body he ascribed an equal, if not a higher, significance than van Helmont himself, following the latter in this as in similar questions. Sylvius had a predilection for comparing chemical with physiological and pathological pro- ceases, which frequently led him into error. Medicine as a whole, he considered, ought simply to be applied chemistry. That these one-sided endeavours were bound to miscarry, considering the state of chemical knowledge at that time, requires no demonstration. And it is equally easy to understand why his chemical doctrines brought less benefit to medicine than to chemistry, seeing that educated physicians, if they wished to comprehend them, were compelled to enter minutely into the study of chemical questions* This^applied in a very special degree to the new remedies, the prepara- tion and rational application of which presupposed a know- ledge of chemistry. Sylvius, addicted as he was to the ufie of heroic medicines, did not hesitate to prescribe lapis
in SYLVIUS AND TAOHENICTS 87
infernalis (nitrate of silver), subljmate and zinc vitriol for internal use; and he was particularly enthusiastic about antimonial and mercurial preparations.
While there are but few discoveries in pure chemistry by Sylvius himself to chronicle, his pupil Otto Tachenius proved an independent investigator, to whom the science is indebted both for extremely valuable observations and for speculations deduced from these. Of his life we only know that he was born at Herford in Westphalia, and that, after moving about from place to place as an apothecary's assistant, he applied himself to the study of medicine in Italy towards the middle of the seventeenth century, and practised in Venice as a physician. Although he attached the greatest weight to clear relations between chemistry and medicine, he had no hesitation in working mischief with secret remedies. Tachenius was the last iatro-chemist of note who followed the doctrines of Sylvius with enthusiasm. In addition to him may be mentioned here the famous English physician Willis (db. 16 75), -who likewise advocated similar views.
Tachenius, among his other valuable observations, con- tributed materially to elucidating that problem which Boyle considered the most important of all, viz. a knowledge of the composition of bodies. It was with him that the first pointed definition of the term " salt," as a compound of an acid and an alkali, originated. His statements on the com- position of various compounds show great acuteness, which iS also seen in the value he attached to certain reactions as tests for different substances. While Tachonius thus laid the foundations of qualitative analysis in a more systematic manner than his predecessors, his attention was also directed to the quantitative proportions in which substances react chemically, — a point to which hardly any attention had hitherto been paid ; and this he exemplified with tolerable accuracy bynoting the increase in weight which took place when lead was transformed into minium. His writings, and also those of his master Sylvius, treat for the most part of subjects chiefly of medical interest, but, as we have just seen, facts
88 THE IATRO-OHEMICAL PERIOD CHAP.
and opinions of importance to chemistry are also recorded in them.
If we wish to arrive at the main result which the iatro- chemical doctrines produced upon the development of chem- istry, we must particularly bear in mind the point already touched upon, viz. that the study of chemistry by physicians who had had a sound education helped materially to shape its course on scientific lines. Notwithstanding the numerous errors and fantastic conceptions in which the iatro-chemists were involved, we come across many very striking views, — views which exercised a marked influence upon the whole tendency of the succeeding epoch. Of these we would mention here: (1) the recognition of the more intimate components of salts, and the clearer comprehension of what was meant by the terms " chemical compound " and " chem- ical affinity," by a knowledge of which the chief aim of chemistry, i.e. the investigation of the true composition of bodies, was effectively advanced ; and (2) the recognition of the analogy between the processes of combustion and the calcination of the metals on the one hand, and respiration on the other. These were doctrines of very great weight indeed. The phlogistic hypothesis, too, which predominated during the greater portion of the eighteenth century, was indicated by many of the iatro-chemists ; i.e. many of the latter had ideas upon combustion which approximated to those of the phlo- gistonists. Lastly, van Helmont's work upon gases exercised the greatest influence on the development of pneumatic chemistry, from which the impulse to the great reform of our science at the end of the 18th century sprang.
It is thus evident that many of the aims of the phlo- gistonists were intimately connected with the observations and opinions proper of the iatro-chemists. And while the medico-chemical opinions of the latter were rudely upset after the middle of the seventeenth century, their facts and theories appertaining to chemistry were the means of guiding the latter into scientific paths.
in GEORGIUS AGKEOOLA, PAUSSY AND