RICHARDS. — SIGNIFICANCE OF CHANGING ATOMIC VOLUME, 5 



affinity of a substance for itself is not unlike that of the substance for 

 another, no great contraction or expansion occurs on mixing. Thus 

 benzol and tuluol when mixed scarcely change in volume at all, while 

 alcohol and water contract considerably. That is just what would be 

 expected if affinity is the cause of contraction. 



In order to use such facts it is not necessary to imagine an atomic 

 theory adapted to them. Such a theory is ventured upon at the end of 

 this paper, but the facts are significant without it. One only has to bear 

 in mind that liquid and solid substances resist compression, and hence 

 that when we find them compressed we have reason to believe that 

 pressure has been applied upon them. It is rather a matter of common 

 sense than a hypothetical abstract conception. 



In order to present in a clear light the complications involved in the 

 study of even a simple series of cases of chemical compression, the facts 

 concerninij the molecular volumes of several metals and their oxides are 

 recorded and discussed below. 



Molecular Volumes of Oxides. 



