60 WATT. 



(referred to in Mr. Cavendish's), which was read June 

 1783, and written before April of that year, says nothing 

 of Mr. Cavendish's theory, though he mentions his experi- 

 ment. 



Several propositions then are proved by this statement. 



First, That Mr. Cavendish, in his paper, read 15th Jan- 

 uary, 1784, relates the capital experiment of burning oxy- 

 gen and hydrogen gases in a close vessel, and finding pure 

 water to be the produce of the combustion. 



Secondly, That, in the same paper, he drew from this 

 experiment the conclusion that the two gases were con- 

 verted or turned into water. 



Thirdly, That Sir Charles Blagden inserted in the same 

 paper, with Mr. Cavendish's consent, a statement that the 

 experiment had first been made by Mr. Cavendish in sum- 

 mor 1781, and mentioned to Dr. Priestley, though it is not 

 said when, nor is it said that any conclusion was mentioned 

 to Dr. Priestley, nor is it said at what time Mr. Cavendish 

 first drew that conclusion. A most material omission. 



Fourthly, That in that addition made to the paper by 

 Sir Charles Blagden, the conclusion of Mr. Cavendish is 

 stated to be, that oxygen gas is water deprived of phlo- 

 giston ; this addition having been made after M. Lavoisier's 

 memoir arrived in England. 



It may further be observed, that in another addition to 

 the paper which is also in Sir C. Blagden' s handwriting, and 

 which was certainly made after M. Lavoisier's memoir had 

 arrived, Mr. Cavendish for the first time distinctly states, 

 as upon M. Lavoisier's hypothesis, that water consisted of 

 hydrogen united to oxygen gas. There is no substan- 

 tial difference, perhaps, between this and the conclusion 

 stated to have been drawn by Mr. Cavendish himself, that 

 oxygen gas is water deprived of phlogiston, supposing 

 phlogiston to be synonymous with hydrogen ; but the for- 

 mer proposition is certainly the more distinct and unequi- 

 vocal of the two : and it is to be observed that Mr. Caven- 

 dish, in the original part of the paper, i. e. the part read 

 January 1784, before the arrival of Lavoisier's, considers 

 it more just to hold inflammable air to be phlogisticated 

 water than pure phlogiston (p. 140.) 



We are now to see what Mr. Watt did ; and the dates 



