88 EXPERIMENTS OF DULONG, AND THE 



I am acquainted, are those of M. Dulong, pub- 

 lished in the Annales de Chimie et de Physique, 

 xxxi. 154; as in the following table, which re- 

 presents their refractive power and specific gra- 

 vity, at the same temperature and pressure of 

 the atmosphere, to which I have added their 

 atomic composition. 



TABLE I. 



Refractive Power. Specific Gravity. 



Atmospheric air 1-000 1-000 



Oxygen -924 1-026 



Hydrogen .... 470 685 



Nitrogen 1-020 976 



Deutoxide of Nitrogen .. 1-030 O2Nl 1-039 



Protoxide of Nitrogen ... 1-710 O 1 N 1 . . . 1-527 



Carbonic Oxide M57 O 1 C 1 -972 



Carbonic Acid 1-526 O2Cl 1-524 



Marsh Gas 1-504 H2C1 -555 



Olefiant Gas 2-302 H2 C2 -980 



Hydrocyanic Acid 1-531 C2NlHl .... -944 



Hydrochloric Acid 1-527 Cl. 1 H 1 '1-245 



Ammonia 1-309 Nl H3 -591 



Chlorine 2-623 2-470 



Cyanogen 2-832 C2Nl 1-818 



Sulphuretted Hydrogen.. 2-187 Si Hi 1-178 



Sulphurous Acid 2-260 S O2 2-247 



Hydrochloric .Ether 3-720 C 4 H 5 Cl. 1 2-234 



Phosgene Gas 3-936 3-442 



Sulphuret of Carbon .... 5-110 2-644 



Sulphuric Either 5-197 2-580 



From the above table we perceive, that there 

 is no uniform relation between the refractive 

 power of gases and what is called their specific 

 heat, as admitted by M. Dulong; while it is 



