42 MEMOIR OF DK. DALTON, AND 



from other substances." There is an admirable clear-sighted- 

 ness in his short and rapid conclusions. The same law of 

 equal expansion of gases was published six months later by 

 Gay Lussac, and is often called by his name. Dr. Ure says 

 the experiments were made by Gay Lussac with much more 

 care and exactness, but the newest results obtained by Reg- 

 nault by no means speak so in favour of Gay Lussac. The 

 difference between his results and Dalton's were only trifling. 

 Gay Lussac gave the expansion per degree at 480, Dal ton 

 483, Regnault 491. In this country we have generally used 

 Gay Lussac's for no sufficient reason. On the Continent 

 Dalton has almost been entirely deprived of his merit, and is 

 not even mentioned in connection with it in many French and 

 German works : but such circumstances are unfortunately of 

 constant occurrence. It is difficult to find the reason of this, 

 but it happens so often that our countrymen are quite omitted 

 in their works, that it must in a great measure arise from 

 their neglect of our literature. This certainly must be the 

 cause, as we find that both French and Germans of high name 

 can treat latent heat without even mentioning the name of 

 Black, whose claims are not even disputed ; this last occurs 

 even with the very systematic Gmelin. We can readily 

 imagine how some of the other papers of Dalton have been 

 overlooked as merely additions to a subject, whereas he who 

 gives the polish and establishes the law has been allowed the 

 entire credit. They were certainly put within the reach of 

 inquirists, as he says in a letter quoted in Dr. Henry's life of 

 him, p. 50. " My lately published essays on gases, &c., toge- 

 ther with the more recent ones read at our society, and of which 

 I gave the result in my late lectures, have drawn the attention 

 of most of the philosophers of Europe. They are busy with 

 them at London, Edinburgh, Paris, and in various parts of 

 Germany, some maintaining one side and some another. The 

 truth will surely out at last." Although not alluding specialljn 



