889 



we calculated 0=:1,3 from ♦he ethyl-oxides. Tf we had a priori 

 assumed ()=l.o, we should have calculated Crcsol = J5,79. 



1 might add other examples to these, but those given here suffice 

 ill my opinion to draw the following conclusions: 



1. The volume of the molecules of normal substances may be 

 found from the critical circumstances. 



2. The volume of the molecules is equal to the sum of the volumes 

 of the atoms contained in it. 



3. The volume of an atom is not constant, but depends also on 

 the atoms to which it is bound, and the way in which it is bound 

 to others. 



4. By normal substances we understand such as do not associate 



or dissociate. For acetic acid 10.415 is found foi- — ^ whereas C^H^Oj 



Pk 



would lead to 7,823 at the most. 



5. The view that the volume of an atom is determined by the 

 size of the orbits of the electrons holds out the prospect to determine 

 the modification of the size in case of mutual binding. 



I had just commenced this investigation on the size of l>, when I 

 received the copies of nine treatises by Albert P. Mathkws on the 

 value of a, in which very remarkable results ha\e been obtained. 

 They appeared in the "Journal of Physical Chemistry" of 1913. 



APPENDIX. 



The comparison of Benzene with Naphthaline has given me the 

 conviction that the smallness of CgH,, as was indeed to be expected, 

 must not be ascribed to the H-atoms, but to the C-atoms. For 



naphthaline — - is equal to 18.91. Now naphthaline is equal to twice 



Pk 



2 5 



— benzene + 2 C or — benzene 2 H. We have, therefore, the 



3 ' 3 



equations : 



18.91 ^ ^Xil-73 + -iO 



o 



and 18.91= |xii-73 — 2H 



or 18.91 = 15.64 + 2C 



and 18.91 = 19.55 — 2H, 



57* 



