Chemistry was deprived of these two illustrious phi losophers, Bergman and Scheele, almost at the same time. Bergman died in 1784, at the baths of Mcdwi, in the 49th year of his age, crowned with glory, after a life spent in the most laborious industry. Scheele was snatched away in 1786, in the 44th year of his age. For about six months previous to his death, lie had been se verely afflicted with the gout. When he began to per ceive that his end was approaching, he was induced, from a principle of gratitude, to marry the widow of his predecessor. The ceremony was performed on the 19th of May, while Scheele lay on his death-bed. On the 21st, he left her by his will the whole of his property ; and the same day on which he had so tenderly provided for her, be died. " Thus," says Dr Crell, t• in less than two years, the world lost Bergman and Scheele, two men of whom Sweden, rich as she is in great and learned men, has the strongest reason to be proud ; two chemists who were equally beloved and lamented by their contem poraries, and whose names will be remembered by the remotest posterity with gratitude and reverence." While these philosophers were employed in cultivat ing chemistry in Sweden, discoveries were made in Scot land which changed the apparatus and the mode of rea soning, reduced under the dominion of chemistry a num ber of invisible substances which had been considered formerly as too subtile for exertion, and thus occasioned a complete revolution in the science. Dr Joseph Black, from whom these discoveries originated, was born in liourdeaux, in 1728. His father was a native of Belfast, but of a Scotch family residing in Aberdeenshire. Dr Black was educated in Belfast, and completed his educa tion at the universities of Glasgow and Edinburgh. He discovered, after an ingenious investigation, that lime stone, and the mild alkalies, are compounds of lime and pure alkalies, with an aerial fluid, to which he gave the name of fixed air. This discovery led to the origin of pneumatic chemistry.' Mr Cavendish soon after inves tigated the properties of fixed air and hydrogen gas. About the year 1770, the subject was taken up by Dr Priestley, who discovered a great variety of aerial fluids, and acquired a most splendid reputation. No man, not even excepting Scheele, ever began the cultivation of chemistry under greater disadvantages than Dr Priest ley, and yet few have made more numerous or more important discoveries. lie was an obscure dissenting clergyman, extremely unpopular in consequence of his opinions, which involved him in almost perpetual con troversy ; his income was exceedingly small, yet he was loaded with a family, and obliged to spend most of the day in teaching to be able to support them. He was to
tally ignorant of chemistry, unprovided with any appa ratus, and not in possession of the means of supplying one. These circumstances, which at first sight seemed to preclude the possibility of his entering upon the che mical career, probably when coupled with his great abi lities and activity, contributed essentially to his ultimate success.
The splendid discoveries of the British chemists drew the attention of Lavoisier to the subject as early as the year 1770. Ile repeated and verified all their experi ments of importance, together with those of the German chemists. He was early satisfied of the imperfections of the Stahiian theory, with which the new discoveries in pneumatic chemistry could not be reconciled ; and after a most elaborate and ingenious investigation, persevered in for a series of years, with the utmost application, he succeeded in establishing a theory nearly the reverse of that of Stahl. For several years after he had satisfied himself of the truth of his opinions, he was not able to produce a single convert either in France or in any other country. At last, Mr Cavendish,f by discovering the composition of water and of nitric acid, removed the grand objections to his opinions, and enabled him to ex plain his new doctrine in a satisfactory manner. Upon this Mr Berthollet declared himself a convert in 1785. His example was followed by Fourcroy ; and in 1787, Morveau, during a visit to Paris, was convinced of his former mistakes, and induced to embrace the same opi nions. The example of these eminent men was followed by that of all the young chemists in France. Mr Kirwan, who had acquired a great reputation by his chemical writings, had published a defence of the doctrine of phlogiston. This essay Mr Lavoisier got translated into French, and it was published, with a refutation, by some eminent chemist, at the end of each section. The refuta tion convinced Mr Kirwan, and induced him to embrace the Lavoisierian theory. His example was followed by Dr Black, and by almost all the eminent British che mists. Indeed, Dr Priestley was almost the only one who did not renounce the phlogistic theory.
Lavoisier and his associates, to make their victory still more certain and complete, invented a new chemical nomenclature, which they proposed, in 1787, as a sub stitute for the old. This nomenclature they adopted in all their writings. A violent controversy was the result, which terminated in the complete triumph of the French nomenclature in every country in Europe.