322 Lord Brougham on the Composition of Water. 



Cavendish does in 1784, and that his reference to the evolution of latent 

 heat renders it more distinct than Mr Cavendish's. 



Thirdly, That there is no proof, nor even any assertion, of Mr Caven- 

 dish's theory (what Sir C. Blagden calls his conclusion) having been 

 communicated to Dr Priestley before Mr Watt stated his theory in 1783, 

 still less of Mr Watt having heard of it, while his whole letter shews that 

 he never had been aware of it, either from Dr Priestley, or from any other 

 quarter. 



Fourthly, That Mr Watt's theory was well known among the members 

 of the Society some months before Mr Cavendish's statement appears to 

 have been reduced into writing, and eight months before it was presented 

 to the Society. We may, indeed, go farther, and affirm, as another de- 

 duction from the facts and dates, that, as far as the evidence goes, there 

 is proof of Mr Watt having first drawn the conclusion, at least that no 

 proof exists of any one having drawn it so early as he is proved to have 

 done. 



Lastly, That a reluctance to give up the doctrine of Phlogiston, a kind 

 of timidity on the score of that long-established and deeply-rooted opi- 

 nion, prevented both Mr Watt and Mr Cavendish from doing full justice to 

 their own theory, while Mr Lavoisier, who had entirely shaken off these 

 trammels, first presented the new doctrine in its entire perfection or con- 

 sistency.* 



All three may liave made the important step nearly at the same time, 

 and unknown to each other ; the step, namely, of concluding from the 

 experiment, that the two gases entered into combination, and that water 

 was the result ; for this, with more or less of distinctness, is the inference 

 which all three drew. 



But there is the statement of Sir Charles Blagden to shew that Mr La- 

 voisier had heard of Mr Cavendish's drawing this inference before his 

 (Mr Lavoisier's) capital experiment was made ;t and it appears that Mr 

 Lavoisier, after Sir C. Blagden's statement had been embodied in Mr Ca- 

 vendish's paper and made public, never gave any contradiction to it in 

 any of his subsequent memoirs which are to be found in the Me'moires 



" It could scarcely be expected that Mr Watt, writing and publishing for the 

 first time, amid the distractions of a large manufacturing concern, and of exten- 

 sive commercial affairs, could compete with the eloquent and practised pen of 

 so great a writer as Lavoisier; but it seems to me, who am certainly no im- 

 partial judge, that the summing up of his theory (p. 333 of his paper), here 

 quoted p. 321, is equally luminous and well expressed as are the conclusions of 

 the illustrious French .■hemist. [Note bv Mr James Watt.] 



-j- In the letter which Sir Charles Blagden addressed to Professor Crell, and 

 which appeared in Crell's Annalen for 1786, professing to give a detailed history 

 of the discovery, he says expressly, that he had communicated to Lavoisier the 

 conclusions both of Cavendish and Wait. This last name appears in that letter 

 for the first time in the recital of the verbal communications of the Secretary of 

 the Royal Society, and is never mentioned by Lavoisier. [Note by Mr James 

 Watt. ] 



