CHEMISTRY. 



WM approaching, he wii induced, from a principle 



~~* of gratitude, to marry the widuw of hit predecesnor. 

 The ceremony wai performed on the 19th of May, 

 while Sclit-clc lay on his death-bed. On the 21 it, 

 he left her by hit will the whole of his property ; and 

 the Mine day on which he had so tenderly provided 

 for her, he died. " Thui," aayi Dr Crcll, " in lest 

 than two years, the world lost Bergman and Scln-elc, 

 two men of whom Sweden, rich as she it in great 

 and learned men, has the strongest reason to be 

 ]>roud ; two chemists who were equally beloved and 

 lamented by their contemporaries, and whose names 

 will be remembered by the remotest posterity with 

 gratitude and reverence." 



While these philosophers were employed in culti- 

 vating chemistry in Sweden, discoveries were made 

 in Scotland which changed the apparatus and the 

 mode of reasoning, reduced under the dominion of 

 chemistry a number of invisible substances which had 

 been considered formerly as too subtile for exertion, 

 and thus occasioned a complete revolution in the sci- 



liUcV. once. Dr Joseph Black, from whom these discove- 

 ries originated, waa born in Bourdeaux, in 1728. 

 His father was a native of Belfast, but of a Scotch 

 family residing in Aberdeen shire. Dr Black was 

 educated in Belfast, and completed his education at 

 the universities of Glasgow and Edinburgh. He 

 discovered, after an ingenious investigation, that 

 limestone, and the mild alkalies, are compounds of 

 lime and pure alkalies, with an aerial fluid, to which 

 he gave the name of jlxed air. This discovery led 



jvendisli. lo lnc or| g> n of pneumatic chemistry. Mr Caven- 

 dish soon after investigated the properties of fixed 

 air and hydrogen gas. About the year 1770, the 



Priestley, subject was taken up by Dr Priestley, who discover- 

 ed a great variety of aerial fluids, and acquired a 

 roost splendid reputation. No man, not even ex- 

 cepting Scheek*, ever began the cultivation of che- 

 mistry under greater disadvantages than Dr Priest- 

 ley, and yet few have made more numerous or more 

 important discoveries. He was an obscure dissent- 

 ing clergyman, axtremely unpopular in consequence 

 of his opinions, which involved him in almost per- 

 petual controversy ; 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 totally ignorant of chemis- 

 try, unprovided with any apparatus, and not in pos- 

 session of the means of supplying one. These cir- 

 cumstances, which at first sight seemed to preclude 

 the possibility of hisentcring upon the chemical career, 

 probably when coupled with his great abilities and ac- 

 tivity, contributed essentially to bis ultimate success. 



The splendid discoveries of the British chemists 

 drew the attention of Lavoisier to the subject as 



I.jroi<ier. early as the year 1770. He repeated and verified all 

 their experiments of importance, together with those 

 of the German chemists. He was early satisfied of 

 the imperfections of the Stahlian theory, with which 

 the new discoveries in pneumatic chemistry could not 

 be reconciled ; and after a most elaborate and inge- 

 nious investigation, persevered in for a series of years, 

 with the utmost application, he succeeded in esta- 

 blishing a theory nearly the reverse of that of Stahl. 

 Fr several years after he had satisfied himself of the 



truth of his opinions, he was not able to produce a History, 

 single convert either in France or in any other conn- ~~Y~~ 

 try. At last, Mr Cavendish, by discovering the 

 composition of water and of nitric acid, removed 

 the grand objections to his opinions, and enabled him 

 to explain his new doctrine in a satisfactory manner. 

 Upon this Mr Berthoilet 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 opinions. 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 pub- 

 lished 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 refutation 

 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 

 chemists. 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 che- 

 mical nomenclature, which they proposed, in 1787. 

 as a substitute for the old. This nomenclature they 

 adopted in all their writings. A violent controversy 

 was the riMilt, which terminated in the complete 

 triumph of the French nomenclature in every coun- 

 try in Europe. 



Such is a concise view of the progress of chcniis- Davy, 

 try down to our own time. Within these few years, 

 very splendid additions have been made to the sci- 

 ence, especially by the sagacity of Mr Davy. And 

 at present, in consequence of the recent and unex- 

 pected galvanic discoveries, the Lavoisierian theory 

 stands a considerable chance of being new modelled, 

 if not in a great measure overthrown. Several im- 

 portant and necessary modifications have already ta- 

 ken place, and others not less important will proba- 

 bly follow. 



We shall endeavour in this article to give a con- 

 cise but comprehensive view of the present state of 

 the science. From the uncertainty to which che- 

 mical theory is liable, and the improbability of ever 

 being able to reach absolute certainty, though every 

 new modification and improvement is probably an 

 approximation, we cannot avoid tailing into error 

 when we attempt to theorise. To thin we are par- 

 ticularly liable in one very important bianch of the 

 science, that namely which treats of heal, which 

 is still very vague, even in its best established points. 

 But we shall endeavour to avoid error as far as is in 

 our power, by adhering closely to accurate experi- 

 mental details, and by pointing out, as clearly a . we 

 can, what is certain, from what is still doubttul or 



pothetic. 



We shall divide this article into three Parts. In the 

 first, we shall treat of the elements of the . science. 

 In the second, we shall take a chemical view of na- 

 ture. In the third, we shall give a short sketch of 

 the most important chemical apparatus. 



hype 



