oil the Specific JVeight of Chemical Compounds. 

 Table {continued). 



179 



From this table we see that the bodies contained in the 

 several groups following possess equal atomic volumes. 



Bromine, chlorine, iodine, cyanogen, chromium, molybde- 

 num, wolframium, iron, cobalt, copper, manganese, nickel, 

 iridium, osmium, palladium, platinum, rhodium. 



The atomic volume of silver is double that of gold. 



potassium ... sodium. 



The atomic volume of a chemical compound is hardly ever 

 equal to the sum of the primitive atomic volumes of its ele- 

 ments. For instance, the atomic volume of chlorine = 160, 

 that of sulphur = 101 ; but the atomic volume of the com- 

 pound S CI is not = 160 + "101 = 261, but according to ob- 

 servation it is = 225. Consequently, in this compound either 

 both or one of the elements have different atomic volumes 

 from their primitive ones. 



Only such compounds will be examined as we can con- 

 sider as binary. 



If the atomic volume of a compound is greater than the 

 primitive atomic volumes of either of its components, we can- 

 not tell whether one or both of the elements are contained in 

 it with an atomic volume different from their primitive one; 

 but we know for certain that one element in a compound 

 does not possess its primitive atomic volume if the atomic 

 volume of the compound is smaller than the primitive atomic 

 volume of that element. It is not as yet possible to state for 

 every compound, which element enters into it with its primi- 

 tive atomic volume, or whether both acquire different ones. 

 It is only possible to state this with a great degree of proba- 

 bility for such classes of compounds as have an analogous 

 composition, so that in all the compounds there is one com- 

 mon element. 



Schroder has found, namely, that if we have a series of 

 analogous bodies, A O, BO, CO, whose atomic volumes we 

 know, and if we know also the primitive atomic volumes of 

 A, B, C, we shall always obtain the same remainder if from 

 the atomic volume of A O we subtract the primitive atomic 

 volume of A, from the atomic volume of BO, the primitive 



N2 



