CORRESPONDENCE. 271 



The war did not wholly break off communication 

 with men of science whom he had known in Great 

 Britain, as is shown by the following letter : 



FROM DR. JOHN MURRAY. 



EDINBURGH, February 5, 1813. 



In a letter which I had very lately from Mr. 



Griscom of New York, he mentioned to me that you are 

 not a convert to Davy's opinion on the oxy-muriatic and 

 muriatic acids. It does not gain ground, I think, here ; 

 indeed, I have scarcely heard of any chemist of eminence 

 having decidedly embraced it. In one of the latest volumes 

 of the " Annales de Chemie " there are two excellent papers 

 in opposition to it, one by Berzelius, and another a report by 

 Berthollet and Vauquelin. If you have seen the late vol- 

 umes of Nicholson, you will have observed that the contro- 

 versy in which I have been engaged on this subject rests 

 much on the experiment of obtaining water by heat from 

 the salt formed by the combination of muriatic and ammoni- 

 acal gases. Sir Humphrey visited Edinburgh a few months 

 ago, and at that time performed the experiment with Dr. 

 Hope, and a very inconsiderable quantity of water was ob- 

 tained. The experiment, however, was conducted in a man- 

 ner very liable to fallacy. I have repeated it within these 

 few days with Dr. Hope, in a less exceptionable manner, and 

 a larger quantity of water was obtained. None ought to 

 appear, according to Sir Humphrey's opinion 



