248 ^^ SUBTERRANEAN HEAT. 



curious facts they have made known, they have employed an 

 insufficient hypothesis. 1st, Tliey have considered the gas 

 in question as a compound of nitrous gas and ether ; while it 

 is composed of gaseous ether, nitrous gas, nitrous add, azote, 

 oxide of azote, carbonic acid, and acetic acid, in short of all 

 the substances capable of assuming the gaseous state, in the 

 various circumstances under which they are found. 2dly, 

 They have supposed ether to be a substance always identi- 

 cally the same, so that they neglected to analyse nitric ether, 

 atid establish its peculiar characters. 3dly, In consequence 

 of this opinion they have been led to ascribe to a preexist- 

 ing nitrous gas phenomena, that are owing to a decomposi-- 

 tion of nitnc ether. 

 If the process After having discussed the opinion and experiments of the 

 •were varied, Dutch chemists, Mr. Thenard concludes his paper by ob- 

 would differ* Serving, that he has considered only the products and phe- 

 nomena obtained by given proportions, and under certaiw 

 circumstances. The effects must be different, when these 

 are varied ; and he intends to subject them to experiment : 

 but that above but he has already satisfied himself, that those he has em- 

 given the best, pj^ygfi ij^-e most favourable to the production of nitric ether. 

 The memoirs The committee concluded, that the memoir at large me- 

 InstiTutJ'^ ^^'^ ^^^^^ insertion in the Collection of foreign Papers, and the 

 class adapted their conclusion. 



XVIII. 



Ohservafions on subterranean Heat, made in the Mines of 

 Poullaouen and Huelgoat in Brittany : by J. F. Daubuis- 



SON*. 



Facts resoect- -^ HERE are few questions in natural philosophy, re- 

 ing the interior specting which we are more in want of positive and well esta- 

 earth^wantine ^^ished facts, to deduce consequences from, than that respect- 

 ing the temperature of the interior part of our globe, taken 

 at depths we are able to reach. I have already made known 

 some facts I observed on this subject in the Saxon mines. 



♦ Journal des Mines, February, 1807, p. 119. 



and 



