Dr. Schroedcr'van der Kolk on Gases. 133 



tion. For air the number 29*2440, and for carbonic acid the 

 number 19*0927 was found; but it was herein assumed that 

 between 0° and 100° K changes regularly with the temperature. 

 This is inadmissible ; the new formulae give 



For air .... K = 29-4443 log =1-466041, 



For carbonic acid . K = 19*0949 log = 1-280917, 



which values form the basis of all the calculations in this paper. 



§ IV. On the Connexion between Atomic Weights and Volumes. 

 Gay-Lussac found, as is well known, that the volumes of gases 

 which combine with one another stand to each other in a simple 

 ratio ; from which it follows that the same is the case between 

 atomic weights and densities. Yet by comparing the densities 

 determined by Regnault at 0° and 0*76 metre pressure, this rela- 

 tion is seen to be only approximately correct. 





Density. 



Atomic 

 weight. 



lUlUO 01 



density. 



Product. 



H 



. 0-06926 



1 



1 



0-06926 







. 1-10563 



8 



16 



0-06910 



N 



. 0-97137 



14 



14 



0-06938 



CO 2 . 



. 1-52901 



22 



22 



0-06950 



The differences in the values in the last column are manifestly 

 too great to be ascribed to errors of observation, and they are 

 therefore considered as arising from the deviations in Mariotte 

 and Gay-Lussac's law. For carbonic acid, Regnault found the 

 deviation at 0° and moderate pressure much smaller • and at 100° 

 it totally disappeared. Yet this last result only proceeds from 

 an error in calculation*. 



The formula? of interpolation which have been found render 

 possible a more accurate examination. They give the changes 

 produced by temperature and pressure in the value of k for the 

 formula 



pv = Jcr. 



Since for this case the gases are always compared at the same 

 pressure and temperature, p and r are always equal, and v is 

 proportional to k. It is sufficient, therefore, to compare the 

 values of k for the different gases at the same pressure and tem- 

 perature. This, however, was only possible for the gases H, N, 

 and CO 2 . 



At 4° and 0*76 metre pressure, k is found to be for 



H 422-337 



N ... 30-1094 x 14 = 421-531 



CO 2 ... 19-1340x22=420948 



* Poggendorff's Annalen, vol. cxvi. p. 444. 

 Phil Mag. S. 4. Vol. 31. No. 207. Feb. 1866. L 



