462 



Mr. E. Wilson. 



invariability of the volume of the constituents of the acid radicle 

 in salts of the acid; for instance, in upwards of 60 sulphates, the 

 radicle S0 4 has the same volume 8' 6 0' 4 = 36. It is true, the carbo- 

 nates appear to form an exception to this rule, the radicle C0 3 having 

 in some cases the volume C' 4 / 4 =23, and sometimes* the volume 

 C' 8 0' 4 =19, and curiously enough, the oxalates follow suit in indi- 

 cating two volumes for the radicle C 2 4 , viz., 0^0^=36, and 

 C' 8 0'4=28. 



The observed specific gravities, with a few exceptions, have been 

 taken from Clarke's " Constants of Nature," being No. 255 of the 

 Smithsonian Miscellaneous Collections, a very compact and useful 

 volume, which contains almost all the determinations that have been 

 made by observers in all parts of the world. 



We may now proceed to point out the very fair agreement between 

 results obtained on the present theory and those reached by Professor 

 Loschmidt by quite a different method, namely, by observations on the 

 interdiffusion of gases. A simple inspection of the following table 

 will show that the molecular volumes obtained on the principles of 

 this theory agree very well with those arrived at by Loschmidt. 



Compaiison of the results of the present theory with those obtained 

 by Professor Loschmidt from his experiments on the inter- diffusion 

 of gases. 









Loschmidt. 



Substance. 



Molecular 



Present 







volume. 



theory. 











I. 



II. 



H 2 



H' 2 



8 



7 



7 



CO 



c' 2 o' 2 



26 



25 



25 



N 2 





24 



26 



24 



NO 



N'oO'2 



22 



24 



23 



o 2 



°> 



20 



22 



21 



HC1 



H^Cl^ 



26-5 



26 -3 



26 -3 



CI 2 



CI', 



45 



45-6 



45 -6 



H 2 



h; 2 o; 2 



18 



18 



18 



H 2 S' 



H' 2 S' 4 



32 



33 



33 



co 2 



C' 2 0' 2 



36 



36 



35 



N 2 



N' 3 0's 



34 



37 



35 



so 2 



S' 4 0' 2 



44 



48 



48 



NK 3 





24 



23-5 



22 -5 



CH 4 



C 2 H' 2 



32 



35 



28 



C 2 N 2 



C' 2 N' 2 



56 



54 



56 



Kopp's labours on molecular volumes were devoted chiefly to liquid 

 substances, which are beyond the scope of this inquiry. The follow- 

 ing brief account of his views on the molecular volumes of solids is 

 derived from Miller's " Chemistry." Kopp supposes that, in the case 



