472 JAMES WATT. 



134 and 135 were not there at first ; they are added, and an 

 indication is given as to where they belong ; the writing is no 

 longer that of Cavendish ; these additions are in the hand- 

 writing of Blagden. And it must have been he who gave all 

 the relative details to Lavoisier, for it is not said that Caven- 

 dish held any direct correspondence with him. 



The date of the reading of Cavendish's Memoir was the 15th 

 of January, 1 784. The volume of the Philosophical Trans- 

 actions, of which this Memoir forms a part, did not appear till 

 about six months after. 



Lavoisier's Memoir (volume of the Academy of Sciences for 

 1781)* had been read in November and December, 1783. 

 Various additions were made to it afterwards. The publica- 

 tion took place in 1784. 



This Memoir contained a description of the experiments of 

 June, 1783, at which Lavoisier announces that Blagden was 

 present. Lavoisier adds, that this English physicist informed 

 him " that Cavendish having already burnt inflammable air in 

 closed vessels, had obtained a very sensible quantity of water ;" 

 but he nowhere says that Blagden informed him of the con- 

 clusions that Cavendish had inferred from those same experi- 

 ments. 



Lavoisier declares, in the most express manner, that the 

 weight of the water is equal to that of the two gases that were 

 ignited, unless, contrary to his own opinion, a sensible weight 

 be assigned to the heat and to the light that were disengaged 

 during the experiment. 



This account does not agree with that of Blagden, which, 

 according to all probability, was written as a refutation to 

 Lavoisier's relation, after the reading of Cavendish's Memoir, 

 and before the volume of the Academy of Sciences had reached 

 England. This volume appeared in 1 784, and assuredly it 

 could not have reached London, either when Cavendish read 

 his paper to the Royal Society, or still less when he wrote it. 

 We must remark, besides, that in the passage of Cavendish's 



* The date 1781 appears to be a clerical error for 1784. Translator. 



