15 



one furnished by Mr. Watt, that he examined the nature of the fluid. 

 Experiments thus conducted could not, and did not, lead to any solid 

 conclusion ; Watt suspended his judgment upon them for a twelve- 

 month, and seven years afterwards, we find Priestley expressing 

 himself thus : " / must say, as I did v)hen I was myself a believer in 

 the decomposition of water, that I have never been able to find the 

 full weight of the air in the water produced by the decomposition." 

 And again : " Having never failed, ivhen the experiments were conducted 

 ivith due attention, to procure some acid lohenever I decomposed dephlo- 

 gisticated and inflammable air in close vessels, I concluded that an acid 

 was the necessary result of the union of these two kinds of air, and not wa- 

 ter onhj'^y Compare these statements, Gentlemen, which have stood on 

 public record for half a century, with those of M. Arago, affirming that 

 Priestley was the first who proved, and Watt the first who understood, 

 the conversion of air into water, and ask yourselves, how it is possible in 

 the face of such evidence to sustain a charge against Cavendish, Blag- 

 den, and the printers of the Royal Society's Transactions, of con- 

 spiring to steal a discovery thus acknoicledged to have been derived from 

 Cavendish, and of which the truth, recognised for a moment, was im- 

 mediately afterwards denied by Priestley, and doubted of by Wait. 



In doing this justice to an injured name, I have been led to speak of 

 one whose numerous discoveries attracted in those daj^s the eyes of all 

 Europe to Birmingham, and who deserves to be admired not more for 

 his inventive fertility and indefatigable industry in experiment, than 

 for the honest candour with which he related every fortuitous success 

 and extraneous hint, and the liberal profusion with which he scattered 

 his gold abroad for public use, as fast as he drew it from the mine. 

 It has been one of the charges, Gentlemen, against this Association, 

 that an analysis of the character of Priestley formed a part of its early 

 transactions : that character, drawn by a hand no less judicious than 

 skilful*, regarded science alone, and contained not a single particle of 

 political or polemical alloy : if it had, being in the chair when it was 

 read, I should have felt it to be my duty to interfere. Much more 

 would I myself avoid the touching from this chair on any topic which 

 should have a tendency to excite feelings alien to our pursuits, and de- 

 structive to all social union : but whilst I can well bear to hear our 

 meetings upbraided with such faults as these, there is one point of attack 

 on which I think I ought not to be silent, even though it stands close 

 on the boundaries of those subjects which I would most rigidly exclude. 



* The late Dr. Henry. 



