CHAP. VII. 



OF THE RELATION BETWEEN THE ATOMIC 

 WEIGHTS AND SPECIFIC GRAVITIES OF GA- 

 SEOUS BODIES. 



GAY-LUSSAC, in a paper published in the second 

 volume of the Memoires d'Arcueil, demonstrated, 

 a good many years ago, that when gases com- 

 bine with each other, one volume of the one gas 

 either combines with one volume, or two vo- 

 lumes, or three volumes of the other. Dr. Prout, 

 in a paper inserted in the sixth volume of the 

 Annals of Philosophy, first pointed out the con- 

 nection which existed between the specific gra- 

 vity and the atomic weights of the gases ; and 

 showed that, in general, the specific gravity is 

 equal to the atomic weight multiplied by half 

 the specific gravity of oxygen gas. I propose 

 in this chapter to take a general view of the re- 

 lation between the atomic weights and the spe- 

 cific gravities of all the known gases. 



1. In the preceding chapters we have deter- 

 mined the atomic weights of all the simple bodies 

 which are capable of assuming the gaseous form. 

 Of these there are only four, which are gases 

 in the uncombined state : these are Oxygen, 



Von. I. Q 



