S62 On the Cause of Chemical Propofi-lions. [May, 



ing to 2 ; phosphorus in a soUd state weighs 1'7, ina gaseous 1'67; 

 and arsenic in a solid state 8'31, in a gaseous 8-39. I have already 

 pointed out the correspondence hetween nickel and cobalt, and 

 between tellurium and antimony. On the other hand, zinc and 

 copper, when in the gaseous form, have the same weight ; but they 

 differ considerably in their solid state. Platinum surpasses potassium 

 in the gaseous state only by half the weight of the latter, while ia 

 the solid state it is 29 times heavier. 



There is another point which deserves to be examined, namely, 

 the relation between the specific gravity of a compound body and 

 the contraction which its elements undergo in combining. I have 

 no doubt that by such an examination we should be able to deter- 

 mine not only the specific gravity for the solid state, but likewise 

 the specific gravity of compound volumes in the state of gas ; that 

 is to say, we should be able in that way to measure the contraction 

 which their elements have undergone in combining, Such re- 

 searches it is probable will have considerable influence on the deve- 

 lopement of the theory of atoms. 



Comparative Table of the Specific Weights of Elementary Bodies. 



