VOLUME AT ORDINARY TEMPERATURE 39 



C4H 10 C 6 H 14 C 7 H, 6 C 8 H 18 C 9 H 20 C 1L H 2 4 C J6 H 34 



96-5 127-2 142-5 158-3 174.3 206 286-2 



CH 2 = 15.3 15.3 15-8 16 15.9 16 



the difference for CH 2 is therefore fairly constant at 15*8. 

 But using this value we get 



H 2 = C 4 H 10 - 4 CH 2 = 96.5-63.2 - 33-3, 

 and consequently a negative space occupied by carbon 

 C = CH 2 -H 2 = 15.8-33.3 = -17.5, 



which can only be avoided by allowing very considerable 

 weight to the constitutive influences. 



These and similar points are explained when we consider 

 that the ratio of the volume at ordinary temperatures to 

 that at the absolute zero and it is that to which additive 

 relations refer in the first place is not the same as for 

 corresponding temperatures. In the latter case a very close 

 approximation to proportionality with the volume V at the 

 absolute zero is to be expected, so that the volumes in 

 question may be directly compared. But there exists the 

 relation 



r =v m -t, 



or in words the volume V^ ?t at o exceeds that at the 

 absolute zero by a fixed amount k. According to the law 

 of rectilinear diameter, remembering that the volume at 

 the absolute zero is one-fourth of the critical volume, this 

 becomes for bodies with high critical temperatures 



1, _ 2 73 ^2 



~ 



273 



5. The Space occupied by Matter, and the Intermolecular 



Space. 



We have so far restricted ourselves to spatial relations 

 that can be dealt with empirically, and by introducing the 

 volume at the absolute zero have avoided the distinction of 

 the entire volume into one part occupied by matter and 

 another which is not. This point of view is that of the 



