1813.] Dr, Joseph Wiestley^ 91 



tary course delivered by Mr. Turner, of Liverpool. He was 

 not in possession of any apparatus, nor acquainted with the 

 method of performing chemical experiments ; and his circum- 

 stances were such that he could neither lay out a great deal of 

 money on experiments, nor could he hope, without a great deal 

 of expense, to make any great progress in his investigations. 

 These circumstances, which at first sight seemed so adverse, were 

 I believe, of considerable service to him, and contributed very 

 much to his ultimate success. The branch of chemistry which 

 he selected was new. An apparatus must be invented before any 

 thing of importance could be effected ; and as simplicity is 

 essential in every apparatus, he was likely to contrive the best, 

 whose circumstances obliged him to attend to economical con- 

 siderations. 



Though the investigation of the properties of air had been 

 prosecuted with considerable success by Boyle; and though 

 Hales Jiad demonstrated the possibility of extracting air from a 

 great variety of substances by very simple processes; and though 

 Dr. Black had ascertained that the air which exists in limestone, 

 and which is separated during the fermenting of malt liquors^ 

 possesses properties different from common air ; it can scarcely 

 be said that pneumatic chemistry was properly begun till Mr. 

 Cavendish published his valuable paper on carbonic acid and 

 hydrogen gas in the year 1766'. He first pointed out the method 

 of examining the properties of gaseous bodies, and invented an 

 apparatus for the purpose, nearly similar to one employed by 

 Mayow about a century before ; but of the existence of which 

 Mr. Cavendish was ignorant. Dr. Priestley was the inventor of 

 the apparatus still used by chemists in pneumatic investigations. 

 It is greatly superior to that of Mr. Cavendish ; and indeed as 

 convenient as can well be desired. Were v^^e indebted to him 

 for nothing else than this apparatus, it would deservedly raise his 

 name very high. 



The discoveries of Dr. Priestley in pneumatic chemistry are 

 so numerous that I cannot even attempt a bare enumeration of 

 them; but must rest satisfied with a general outline. His first 

 paper was published in 177^. It was on the method of impreg- 

 nating water with fixed air. The experiments contained in it 

 were made in consequence of his residing near a brewery at 

 Leeds. This accidental position, therefore, was in some measure 

 the cause of his beginning his great chemical career. This 

 pamphlet was immediately translated into French ; and at a 

 meeting of the College of Physicians in London, they addressed 

 the Lords of the Treasury, pointing out the advantage that might 

 result from water impregnated with fixed air, according to Dr. 

 Priestley's method, in cases of the scurvy at sea. His next essay 

 was published ia tlie Philosophical Transactions, and procured 



