Manchester Memoirs, Vol. Ivii. (19 13), No. 10. 37 



I have mentioned Watt as being one of the members 

 of the Lunar Society, and I have therefore given 

 the reproduction of Watt's description of one of his 

 patents, written and signed by him. (See PL VIII.) 

 Watt's investigations into the composition of water were 

 doubtless prompted by Priestley's communication of his 

 discoveries to him at the Lunar Society meetings.^^ 



Priestley played the part of the simple experimental 

 philosopher, and left the conclusions to be drawn by 

 others. He himself describes the role which fortune had 

 allotted to him in the following letter : — 



To Sir Joseph Banks. 



Birmingham, 



23rd June, 1783. 



Dear Sir, 



I certainly meant to submit my paper to the 

 Royal Society, as it contains a series of remark- 

 ably new facts, completely ascertained ; whatever 

 DEDUCTIONS (about which I am not solicitous) be 

 drawn from them.'*" As I have opportunity, I shall 



^^ The literature on the somewhat difficult question concerning the 

 discovery of the composition of water is ample. Amongst the most 

 important contributions are : Muirhead's ' Correspondence of the late James 

 Watt on his discovery of the composition of water.' London, 1846. G. 

 Wilson's 'Life of Cavendish.' London, 1851. Pp. 265 — 445. Kopp's 

 ■• Beitrage,' part iii., p. 237. Braunschweig, 1846. M. Berthelot's 

 'La Revolution Chimique,' pp. 109 — 133. Paris, 1902. (2nd ed.) Sir 

 Edward Thorpe's 'Essays in Historical Chemistry.' (3rd ed.) London, 

 1911. Pp. 79-122. 



■'° ' Dr. Priestley was a discoverer before he was a chemist. In a letter 

 which I received from him a few months before his death, he makes this 

 statement in his usual unaffected manner. It is easy, therefore, to find 

 reason for the occasional uncorrectness of his views. Throughout the whole 

 •course of his life liis attention was never undivided. His mornings were 

 devoted to experiment ; his evenings to political, theological, or meta- 

 physical inquiries. He is an example of how much can be done by small 

 means, when applied with industry and ingenuity . . . .' Davy in his 

 'Collected Works,' vol. vii., p. 118. 



