CHAPTER VII.

OF GLAUBER, LEMERY, AND SOME OTHER CHEMISTS OF THE END OF THE SEVENTEENTH CENTURY.

Hitherto I have treated of the alchymists, or iatro-chemists, and have brought the history of chemistry down to the beginning of the eighteenth century. But during the seventeenth century there existed several laborious chemists, who contributed very materially by their exertions, either to extend the bounds of the science, or to increase its popularity and respectability in the eyes of the world. Of some of the most eminent of these it is my intention to give an account in this chapter.

Of John Rudolf Glauber, the first of these meritorious men in point of time, I know very few particulars. He was a German and a medical man, and spent most of his time at Salzburg, Ritzingen, Frankfort on the Maine, and at Cologne. Towards the end of his life he went to Holland, but during the greatest part of his residence in that country he was confined to a sick-bed. He died at Amsterdam in 1668, after having reached a very advanced age. Like Paracelsus, whom he held in high estimation, he was in open hostility with the Galenical physicians of his time. This led him into various controversies, and induced him to publish various apologies; most of which still remain among his writings. One of the most curious of these apologies is the one against Farmer. To this man Glauber had communicated certain secrets of his own, which were at that time considered as of great value; Farrner binding himself not to communicate them to any person. This obligation he not only broke, but publicly deprecated the skill and integrity of Glauber, and offered to communicate to others, for stipulated sums, a set of secrets of his own, which he vaunted of as particularly valuable. Glauber examines these secrets, and shows that every one of them possessed of any value, had been communicated by himself to Farrner, and to put an end to Farrner’s unfair attempt to make money by selling Glauber’s secrets, he in this apology communicates the whole processes to the public.

Glauber’s works were published in Amsterdam, partly in Latin, and partly in the German language. In the year 1689 an English translation of them was published in London by Mr. Christopher Packe, in one large folio volume. Glauber was an alchymist and a believer in the universal medicine. But he did not confine his researches to these two particulars, but endeavoured to improve medicine and the arts by the application of chemical processes to them. In his treatise of _philosophical furnaces_ he does not confine himself to a description of the method of constructing furnaces, and explaining the use of them, but gives an account of a vast many processes, and medicinal and chemical preparations, which he made by means of these furnaces. One of the most important of these preparations was muriatic acid, which he obtained by distilling a mixture of common salt, sulphate of iron, and alum, in one of the furnaces which he describes.

He makes known the method of dissolving most of the metals in muriatic acid, and the resulting chlorides, which he denominates oils of the respective metals, constitute in his opinion valuable medicines. He mentions particularly the chloride of gold, and from the mode of preparing it, the solution must have been strong. Yet he recommends it as an internal medicine, which he says may be taken with safety, and is a sovereign remedy in old ulcers of the mouth, tongue, and throat, arising from the French pox, leprosy, scorbute, &c. Thus we see the use of gold as a remedy for the venereal disease did not originate with M. Chretiens, of Montpelier. This chloride of gold is so violent a poison that it is remarkable that Glauber does not specify the dose that patients labouring under the diseases for which he recommends it ought to take.--The sesqui-chloride of iron he recommends as a most excellent application to ill-conditioned ulcers and cancers. We see from this that the use of iron in cancers, lately recommended, is not so new a remedy as has been supposed.

He mentions the violent action of chloride of mercury (obviously corrosive sublimate), and says that he saw a woman suddenly killed by it, being administered internally by a surgeon. Butter of antimony he first recognised as nothing else than a combination of chlorine and antimony; before his time it had been always supposed to contain mercury.

He describes the method of obtaining sulphuric acid by distilling sulphate of iron; gives an account of the mode of obtaining sulphate of iron and sulphate of copper, in crystals: the method of obtaining nitric acid from nitre by means of alum, was much improved by him. He gives a particular detail of the way of obtaining fulminating gold. This fulminating gold he says is of little use in medicine; but he gives a method of preparing from it a red tincture of gold, which he considers as one of the most useful and efficacious of all medicines: this tincture is nothing else than chloride of gold. It would take up too much space to attempt an analysis of all the curious facts and preparations described in this treatise on philosophical furnaces; but it will repay the perusal of any person who will take the trouble to look into it. All the different pharmacopœias of the seventeenth century borrowed from it largely. The third part of this treatise is peculiarly interesting. It will be seen that Glauber had already thought of the peculiar efficacy of applying solutions of sulphur, &c. to the skin, and had anticipated the various vapour and gaseous baths which have been introduced in Vienna and other places, during the course of the present century, and considered as new, and as constituting an important era in the healing art. In the fourth part he not only treats of the docimastic processes, so well described by Agricola and Erckern, but gives us the method of making glass, and of imitating the precious stones by means of coloured glasses. The fifth part is peculiarly valuable; in it he treats of the methods of preparing lutes for glass vessels, of the construction and qualities of crucibles, and of the vitrification of earthen vessels.

Another of his tracts is called “The Mineral Work;” the object of which is to show the method of separating gold from flints, sand, clay, and other minerals, by the spirit of salt (_muriatic acid_), which otherwise cannot be purged; also a panacea, or universal antimonial medicine. This panacea was a solution of deutoxide of antimony in pyrotartaric acid; Glauber gives a most flattering account of its efficacy in removing the most virulent diseases, particularly all kinds of cutaneous eruptions. The second and third parts of The Mineral Work are entirely alchymistical. In the treatise called “Miraculum Mundi,” his chief object is to write a panegyric on _sulphate of soda_, of which he was the discoverer, and to which he gave the name of _sal mirabile_. The high terms in which he speaks of this innocent salt are highly amusing, and serve well to show the spirit of the age, and the dreams which still continued to haunt the most laborious and sober-minded chemists. The _sal mirabile_ was not merely a purgative, a virtue which it certainly possesses in a high degree, being as mild a purgative, perhaps the very best, of all the saline preparations yet tried; but it was a universal medicine, a panacea, a cure for all diseases: nor was Glauber contented with this, but pointed out many uses in the various arts and manufactures for which in his opinion it was admirably fitted. But by far the fullest account of this _sal mirabile_ is given by him in his treatise on the nature of salts.

I shall satisfy myself with giving the titles of his other tracts. Every one of them contains facts of considerable importance, not to be found in any chemical writings that preceded him; but to attempt to connect these facts into one point of view would be needless, because they are not such as would be likely to interest the general reader.

1. The Consolation of Navigators. This gives an account of a method by which sailors may carry with them a great deal of nourishment in very small bulk. The method consists in evaporating the wort of malt to dryness, and carrying the dry extract to sea. This method has been had recourse to in modern times, and has been found to furnish an effectual remedy against the scurvy. He recommends also the use of muriatic acid as a remedy for thirst, and a cure for the scurvy.

2. A true and perfect Description of the extracting good Tartar from the Lees of Wine.

3. The first part of the Prosperity of Germany; in which is treated of the concentration of wine, corn, and wood, and the more profitable use of them than has hitherto been.

4. The second part of the Prosperity of Germany; wherein is shown by what means minerals may be concentrated by nitre, and turned into metallic and better bodies.

5. The third part of the Prosperity of Germany; in which is delivered the way of most easily and plentifully extracting saltpetre out of various subjects, every where obvious and at hand. Together with a succinct explanation of Paracelsus’s prophecy; that is to say, in what manner it is to be understood the northern lion will institute or plant his political or civil monarchy; and that Paracelsus himself will not abide in his grave; and that a vast quantity of riches will offer itself. Likewise who the artist Elias is, of whose coming in the last days, and his disclosing abundance of secrets, Paracelsus and others have predicted.

6. The fourth part of the Prosperity of Germany; in which are revealed many excellent, useful secrets, and such as are serviceable to the country; and withal several preparations of efficacious cates extracted out of the metals and appointed to physical uses; as also various confections of golden potions. To which is also adjoined a small treatise which maketh mention of my laboratory; in which there shall be taught and demonstrated (for the public good and benefit of mankind) wonderful secrets, and unto every body most profitable but hitherto unknown.

7. The fifth part of the Prosperity of Germany; clearly and solidly demonstrating and as it were showing with the fingers, what alchymy is, and what benefit may, by the help thereof, be gotten every where and in most places of Germany. Written and published to the honour of God, the giver of all good things, primarily; and to the honour of all the great ones of the country; and for the health, profit, and assistance against foreign invasions, of all their inhabitants that are by due right and obedience subject unto them.

8. The sixth and last part of the Prosperity of Germany; in which the arcanas already revealed in the fifth part, are not only illustrated and with a clear elucidation, but also such are manifested as are most highly necessary to be known for the defence of the country against the Turks. Together with an evident demonstration adjoined, showing, that both a particular and universal transmutation of the imperfect metals into more perfect ones by salt and fire, is most true; and withal, by what means any one, that is endued with but a mean knowledge in managing the fire, may experimentally try the truth hereof in twenty-four hours’ space.

9. The first century of Glauber’s wealthy Storehouse of Treasures.--Many of the processes given in this treatise are mystically stated, or even concealed.

10. The second, third, fourth, and fifth century of Glauber’s wealthy Storehouse of Treasures.

11. New chemical Light; being a revelation of a certain new invented secret, never before manifested to the world.--This was a method of extracting gold from stones. Probably the gold found by Glauber in his processes existed in some of the reagents employed; this, at least, is the most natural way of accounting for the result of Glauber’s trials.

15. The spagyrical Pharmacopœia, or Dispensatory.--In this book he treats chiefly of medicines peculiarly his own; one of those, on which he bestows the greatest praise, is _secret sal ammoniac_, or sulphate of ammonia. He describes the method of preparing this salt, by saturating sulphuric acid with ammonia. He informs us that it was much employed by Paracelsus and Van Helmont, who distinguished it by the name of _alkahest_.

13. Book of Fires.--Full of enigmas.

14. Treatise of the three Principles of Metals; viz. sulphur, mercury, and salt of philosophers; how they may be profitably used in medicine, alchymy, and other arts.

15. A short Book of Dialogues. Chiefly relating to alchymy.

16. Proserpine, or the Goddess of Riches.

17. Of Elias the Artist.

18. Of the three most noble Stones generated by three Fires.

19. Of the Purgatory of Philosophers.

20. Of the secret Fire of Philosophers.

21. A Treatise concerning the Animal Stone.

John Kunkel, who acquired a high reputation as a chemist, was born in the Duchy of Sleswick; in the year 1630: his father was a trading chemist, or apothecary; and Kunkel himself had, in his younger years, paid great attention to the business of an apothecary: he had also diligently studied the different processes of glass-making; and had paid particular attention to the assaying of metals. In the year 1659, he was chamberlain, chemist, and superintendent of apothecaries to the dukes Francis Charles and Julius Henry, of Lauenburg. While in this situation, he examined many pretended transmutations of metals, and undertook other researches of importance. From this situation he was invited, by John George II., Elector of Saxony, on the recommendation of Dr. Langelott and Counsellor Vogt, as chamberlain and superintendent of the elector’s laboratory, with a considerable salary. From this situation he went to Berlin, where he was chemist to the elector Frederick William; after whose death, his laboratory and glass-house were accidentally burnt. From Berlin he was invited to Stockholm by Charles XI., King of Sweden, who gave him the title of counsellor of metals, and raised him to the rank of a nobleman: here he died, in 1702, in the seventy-second year of his age. Kunkel’s greatest discovery was, the method of extracting phosphorus from urine. This curious substance had been originally discovered by Brandt, a chemist, of Hamburg, in the year 1669, as he was attempting to extract from human urine a liquid capable of converting silver into gold. He showed a specimen of it to Kunkel, with whom he was acquainted: Kunkel mentioned the fact as a piece of news to one Kraft, a friend of his in Dresden, where he then resided: Kraft immediately repaired to Hamburg, and purchased the secret from Brandt for 200 rix-dollars, doubtless exacting from him, at the same time, a promise not to reveal it to any other person. Soon after, he exhibited the phosphorus publicly in Britain and in France; whether for money, or not, does not appear. Kunkel, who had mentioned to his friend his intention of getting possession of the process, being vexed at the treacherous conduct of Kraft, attempted to discover it himself, and, after three or four years labour, he succeeded, though all that he knew from Brandt was, that urine was the substance from which the phosphorus was procured. In consequence of this success, phosphorus was at first distinguished by the epithet of _Kunkel_ added to the name.

Kunkel published, in 1678, a treatise on phosphorus, in which he describes the properties of this substance, at that time a subject of great wonder and curiosity. In this treatise, he proposes phosphorus as a remedy of some efficacy, and gives a formula for preparing pills of it, to be taken internally. It is therefore erroneous to suppose, as has been done, that the introduction of this dangerous remedy into medicine is a modern discovery. Kunkel appears to have been acquainted with nitric ether. One of the most valuable of his books, is his treatise on glass-making, which was translated into French; and which, till nearly the end of the eighteenth century, constituted by far the best account of glass-making in existence. The following is a list of the most important of his works:

1. Observations on fixed and volatile Salts, potable Gold and Silver, Spiritus Mundi, &c.; also of the colour and smell of metals, minerals, and bitumens.--This tract was published at Hamburg, in 1678, and has been several times reprinted since.

2. Chemical Remarks on the chemical Principles, acid, fixed and volatile alkaline Salts, in the three kingdoms of nature, the mineral, vegetable, and animal; likewise concerning their colour and smell, &c.; with a chemical appendix against non-entia chymica.

3. Treatise of the Phosphorus mirabilis, and its wonderful shining Pills; together with a discourse on what was formerly rightly named nitre, but is now called the _blood of nature_.

4. An Epistle against Spirit of Wine without an acid.

5. Touchstone de Acido et Urinoso, Sale calido et frigido.

6. Ars Vitraria experimentalis.

7. Collegium Physico-chymicum experimentale, _or_ Laboratorium chymicum.[176]

[176] I have never seen a copy of this last work; it must have been valuable, as it was the book from which Scheele derived the first rudiments of his knowledge.

Nicolas Lemery, the first Frenchman who completely stripped chemistry of its mysticism, and presented it to the world in all its native simplicity, deserves our particular attention, in consequence of the celebrity which he acquired, and the benefits which he conferred on the science. He was born at Rouen on the 17th of November, 1645. His father, Julian Lemery, was _procureur_ of the Parliament of Normandy, and a protestant. His son, when very young, showed a decided partiality for chemistry, and repaired to an apothecary in Rouen, a relation of his own, in hopes of being initiated into the science; but finding that little information could be procured from him, young Lemery left him in 1666, and went to Paris, where he boarded himself with M. Glaser, at that time demonstrator of chemistry at the Jardin du Roi.

Glaser was a _true chemist_, according to the meaning at that time affixed to the term--full of obscure notions--unwilling to communicate what knowledge he possessed--and not at all sociable. In two months Lemery quitted his house in disgust, and set out with a resolution to travel through France, and pick up chemical information as he best could, from those who were capable of giving him information on the subject. He first went to Montpelier, where he boarded in the house of M. Vershant, an apothecary in that town. With his situation there he was so much pleased, that he continued in it for three years: he employed himself assiduously in the laboratory, and in teaching chemistry to a number of young students who boarded with his host. Here his reputation gradually increased so much, that he drew round him the professors of the faculty of medicine of Montpelier, and all the curious of the place, to witness his experiments. Here, too, he practised medicine with considerable success.

After travelling through all France, he returned to Paris in 1672. Here he frequented the different scientific meetings at that time held in that capital, and soon distinguished himself by his chemical knowledge. In a few years he got a laboratory of his own, commenced apothecary, and began to give public lectures on chemistry, which were speedily attended by great crowds of students from foreign countries. For example, we are told that on one occasion forty Scotchmen repaired to Paris on purpose to hear his lectures, and those of M. Du Verney on anatomy. The medicines which he prepared in his laboratory became fashionable, and brought him a great deal of money. The magistery of bismuth (or pearl-white), which he prepared as a cosmetic, was sufficient, we are told, to support the whole expense of his house. In the year 1675 he published his Cours de Chimie, certainly one of the most successful chemical books that ever appeared; it ran through a vast number of editions in a few years, and was translated into Latin, German, Spanish, and English.

In 1681 he began to be troubled in consequence of his religious opinions. Louis XIV. was at that time in the height of his glory, entirely under the control of his priests, and zealously bent upon putting an end to the reformed religion in his dominions. Indeed, from the infamous conduct of Charles II. of England, and the bigotry of his successor, a prospect was opened to him, and of which he was anxious to avail himself, of annihilating the reformed religion altogether, and of plunging Europe a second time into the darkness of Roman Catholicism.

Lemery found it expedient, in 1683, to pass over into England. Here he was well received by Charles II.: but England was at that time convulsed with those religious and political struggles, which terminated five years afterwards in the revolution. Lemery, in consequence of this state of things, found it expedient to leave England, and return to France. He took a doctor’s degree at Caen, in Normandy; and, returning to Paris, he commenced all at once practitioner in medicine and surgery, apothecary, and lecturer on chemistry. The edict of Nantes was revoked in 1685, when James II. had assured Louis of his intention to overturn the established religion, and bring Great Britain again under the dominion of the pope. Lemery was obliged to give up practice and conceal himself, in order to avoid persecution. Finding his success hopeless, as long as he continued a protestant, he changed his religion in 1686, and declared himself a Roman catholic. This step secured his fortune: he was now as much caressed and protected by the court and the clergy, as he had been formerly persecuted by them. In 1699 when the Academy of Sciences was new modelled, he was appointed associated chemist, and, on the death of Bourdelin, before the end of that year, he became a pensioner. He died on the 19th of June, 1715, at the age of seventy, in consequence of an attack of palsy, which terminated in apoplexy.

Besides his System of Chemistry, which has been already mentioned, he published the following works:

1. Pharmacopée universelle, contenant toutes les Operations de Pharmacie qui sont en usage dans la Médicine.

2. Traité universelle des Drogues simples mis en ordre alphabétique.

3. Traité de l’Antimoine, contenant l’analyse chimique de ce mineral.

Besides these works, five different papers by Lemery were printed in the Memoirs of the French Academy, between 1700 and 1709 inclusive. These are as follow:

1. Explication physique et chimique des Feux souterrains, des tremblemens de Terre, des Ouragans, des Eclairs et du Tonnere.--This explanation is founded on the heat and combustion produced by the mutual action of iron filings and sulphur on each other, when mixed in large quantities.

2. Du Camphre.

3. Du Miel et de son analyse chimique.

4. De l’Urine de Vache, de ses effets en médicine et de son analyse chimique.

5. Reflexions et Experiences sur le Sublimé Corrosive.--It appears from this paper, that in 1709, when Lemery wrote, corrosive sublimate was considered as a compound of mercury with the sulphuric and muriatic acids. Lemery’s statement, that he made corrosive sublimate simply by heating a mixture of mercury and decrepitated salt, is not easily explained. Probably the salt which he had employed was impure. This is the more likely, because, from his account of the matter which remained at the bottom of the matrass after sublimation, it must have either contained peroxide of iron or peroxide of mercury, for its colour he says was red.

M. Lemery left a son, who was also a member of the French Academy; an active chemist, and author of various papers, in which he endeavours to give a mechanical explanation of chemical phenomena.

Another very active member of the French Academy, at the same time with Lemery, was M. William Homberg, who was born on the 8th of January, 1652, at Batavia, in the island of Java. His father, John Homberg, was a Saxon gentleman, who had been stripped of all his property during the thirty years war. After receiving some education by the care of a relation, he went into the service of the Dutch East India Company, and got the command of the arsenal at Batavia. There he married the widow of an officer, by whom he had four children, of whom William was the second.

His father quitted the service of the India Company and repaired to Amsterdam with his family. Young Homberg studied with avidity: he devoted himself to the law, and in 1674 was admitted advocate of Magdeburg; but his taste for natural history and science was great. He collected plants in the neighbourhood, and made himself acquainted with their names and uses. At night he studied the stars, and learned the names and positions of the different constellations. Thus he became a self-taught botanist and astronomer. He constructed a hollow transparent celestial globe, on which, by means of a light placed within, the principal fixed stars were seen in the same relative positions as in the heavens.

Otto Guericke was at that time burgomaster of Magdeburg. His experiments on a vacuum, and his invention of the air-pump, are universally known. Homberg attached himself to Otto Guericke, and this philosopher, though fond of mystery, either explained to him his secrets, in consequence of his admiration of his genius, or was unable to conceal them from his penetration. At last Homberg, quite tired of his profession of advocate, left Magdeburg and went to Italy. He sojourned for some time at Padua, where he devoted himself to the study of medicine, anatomy, and botany. At Bologna he examined the famous Bologna stone, the nature of which had been almost forgotten, and succeeded in making a pyrophorus out of it. At Rome he associated particularly with Marc-Antony Celio, famous for the large glasses for telescopes which he was able to grind. Nor did he neglect painting, sculpture, and music; pursuits in which, at that time, the Italians excelled all other nations.

From Italy he went to France, and thence passed into England, where he wrought for some time in the laboratory of Mr. Boyle, at that time one of the most eminent schools of science in Europe. He then passed into Holland, studied anatomy under De Graaf, and after visiting his family, went to Wittemberg, where he took the degree of doctor of medicine.

After this he visited Baldwin and Kunkel, to get more accurate information respecting the phosphorus which each had respectively discovered. He purchased a knowledge of Kunkel’s phosphorus, by giving in exchange a meteorological toy of Otto Guericke, now familiarly known, by which the moisture or dryness of the air was indicated--a little man came out of his house and stood at the door in dry weather, but retired under cover in moist weather. He next visited the mines of Saxony, Bohemia, and Hungary: he even went to Sweden, to visit the copper-mines of that country. At Stockholm he wrought in the chemical laboratory, lately established by the king, along with Hjerna, and contributed considerably to the success of that new establishment.

He repaired a second time to France, where he spent some time, actively engaged with the men of science in Paris. His father strongly pressed him to return to Holland and settle as a physician: he at last consented, and the day of his departure was come, when, just as he was going into his carriage, he was stopped by a message from M. Colbert on the part of the king. Offers of so advantageous a nature were made him if he would consent to remain in France, that, after some consideration, he was induced to embrace them.

In 1682 he changed his religion and became Roman catholic: this induced his father to disinherit him. In 1688 he went to Rome, where he practised medicine with considerable success. A few years after he returned to Paris, where his knowledge and discoveries gave him a very high reputation. In 1691 he became a member of the Academy of Sciences, and got the direction of the laboratory belonging to the academy: this enabled him to devote his undivided attention to chemical investigations. In 1702 he was taken into the service of the Duke of Orleans, who gave him a pension, and put him in possession of the most splendid and complete laboratory that had ever been seen. He was presented with the celebrated burning-glass of M. Tchirnhaus, by the Duke of Orleans, and was enabled by means of it to determine many points that had hitherto been only conjectural.

In 1704 he was made first physician to the Duke of Orleans, who honoured him with his particular esteem. This appointment obliging him to reside out of Paris, would have made it necessary for him to resign his seat in the academy, had not the king made a special exemption in his favour. In 1708 he married a daughter of the famous M. Dodart, to whom he had been long attached. Some years after he was attacked by a dysentery, which was cured, but returned from time to time. In 1715 it returned with great violence, and Homberg died on the 24th of September.

His knowledge was uncommonly great in almost every department of science. His chemical papers were very numerous; though there are few of them, in this advanced period of the science, that are likely to claim much attention from the chemical world. His pyrophorus, of which he has given a description in the Mémoires de l’Académie,[177] was made by mixing together human fæces and alum, and roasting the mixture till it was reduced to a dry powder. It was then exposed in a matrass to a red heat, till every thing combustible was driven off. Any combustible will do as a substitute for human fæces--gum, flour, sugar, charcoal, may be used. When a little of this phosphorus is poured upon paper, it speedily catches fire and kindles the paper. Davy first explained the nature of this phosphorus. The potash of the alum is converted into potassium, which, by its absorption of oxygen from the atmosphere, generates heat, and sets fire to the charcoal contained in the powder.

[177] For 1711, p. 238.

Homberg’s papers printed in the Memoirs of the French Academy amount to thirty-one. They are to be found in the volumes for 1699 to 1714 inclusive.

M. Geoffroy, who was a member of the academy about the same time with Lemery and Homberg, though he outlived them both, and who was an active chemist for a considerable number of years, deserves also to be mentioned here.

Stephen Francis Geoffroy was born in Paris on the 13th of February, 1672, where his father was an apothecary. While a young man, regular meetings of the most eminent scientific men of Paris were held in his father’s house, at which he was always present. This contributed very much to increase his taste for scientific pursuits. After this he studied botany, chemistry, and anatomy in Paris. In 1692 his father sent him to Montpelier, to study pharmacy in the house of a skilful apothecary, who at the same time sent his son to Paris, to acquire the same art in the house of M. Geoffroy, senior. Here he attended the different classes in the university, and his name began to be known as a chemist. After spending some time in Montpelier, he travelled round the coast to see the principal seaports, and was at St. Malo’s in 1693, when it was bombarded by the British fleet.

In 1698 Count Tallard being appointed ambassador extraordinary to London, made choice of M. Geoffroy as his physician, though he had not taken a medical degree. Here he made many valuable acquaintances, and was elected a fellow of the Royal Society. From London he went to Holland, and thence into Italy, in 1700, where he went in the capacity of physician to M. de Louvois. The great object of M. Geoffroy was always natural history, and materia medica. In 1693 he had subjected himself to an examination, and he had been declared qualified to act as an apothecary; but his own object was to be a physician, while that of his father was that he should succeed himself as an apothecary: this in some measure regulated his education. At last he declared his intentions, and his father agreed to them; he became bachelor of medicine in 1702, and doctor of medicine in 1704.

In 1709 he was made professor of medicine in the Royal College. In 1707 he began to lecture on chemistry, at the Jardin du Roi, in place of M. Fagan, and continued to teach this important class during the remainder of his life. In 1726 he was chosen dean of the faculty of medicine; and, after the two years for which he was elected was finished, he was again chosen to fill the same situation. There existed at that time a lawsuit between the physicians and surgeons in Paris; a kind of civil war very injurious to both; and the mildness and suavity of his manners fitted him particularly for being at the head of the body of physicians during its continuance. He became a member of the academy in 1699, and died on the 6th of January, 1731.

The most important of all his chemical labours, and for which he will always be remembered in the annals of the science, was the contrivance which he fell upon, in 1718, of exhibiting the order of chemical decompositions under the form of a table.[178] This method was afterwards much enlarged and improved. Such tables are now usually known by the name of _tables of affinity_; and, though they have been of late years somewhat neglected, there can be but one opinion of their importance when properly constructed.

[178] Mem. Paris, 1718, p. 202; and 1720, p. 20.

M. Geoffroy first communicated to the French chemists the mode of making Prussian blue, as Dr. Woodward did to the English.

Claude Joseph Geoffroy, the younger brother of the preceding, was also a member of the Academy of Sciences, and a zealous cultivator of chemistry. Many of his chemical papers are to be found in the memoirs of the French Academy. He demonstrated the composition of sal ammoniac, which however was known to Glauber. He made many experiments upon the combustion of the volatile oils, by pouring nitric acid on them. He explained the pretended property which certain waters have of converting iron into copper, by showing that in such cases copper was held in solution in the water by an acid, and that the iron merely precipitated the copper, and was dissolved and combined with the acid in its place. He pointed out the constituents of the three vitriols, the green, the blue, and the white; showing that the two former were combinations of sulphuric acid with oxides of iron and copper, and the latter a solution of lapis calaminaris (_carbonate of zinc_) in the same acid. He has also a memoir on the emeticity of antimony, tartar emetic, and kermes mineral; but it is rather medical than chemical. He determined experimentally the nature of the salt of Seignette, or Rochelle salt, and showed that it was obtained by saturating cream of tartar with carbonate of soda, and crystallizing. It is curious that this discovery was made about the same time by M. Boulduc. I have noticed only a few of the papers of M. Geoffroy, junior; because, though they all do him credit, and contributed to the improvement of chemistry, yet none of them contain any of those great discoveries, which stand as landmarks in the progress of science, and constitute an era in the history of mankind. For the same reason I omit several other names that, in a more minute history of chemistry, would deserve to be particularized.