212 Mr. William Sutherland on the 



Mr. John Sutherland. Arnagat's exhaustive study of the 

 compression and expansion of gases, along with Ramsay and 

 Young's work on ethyl oxide, were the groundwork of the 

 research. 



As the true characteristic equations for fluids are the key 

 to many chambers of molecular physics, I have been able to 

 enter many of these, and especially to discover the true law 

 of the parameter A without exception. To give an idea of 

 the scope of these investigations free from detail, I furnish the 

 following table of contents : — 



1. Establishment of characteristic equation for compounds 

 above the region of the critical volume, with proof that there 

 is discontinuity in the liquefaction of compounds. 



2. The same for the gaseous elements, with proof of con- 

 tinuity during liquefaction in their case. 



3. Brief discussion of exceptional compounds such as the 

 alcohols and ethylene. 



4. Establishment of characteristic equation below the region 

 of the critical volume, its main feature being the occurrence 

 in it of the same internal virial constant as in the equation 

 for the region above the critical volume. 



5. A short digression on the general interpretation of 

 Clausius's equation of the virial. 



6. Consideration of Van der Waals's generalization that if 

 each substance has its temperature, pressure, and volume 

 expressed in terms of the critical values as units, one and the 

 same law applies to all bodies ; proof that this is true for 

 elements and compounds separately, above the critical region, 

 and approximately true below. 



7. Five methods of finding the internal virial constant : 

 first, from the expansion and compression of the substance as 

 gas or vapour ; second, from its expansion and compression 

 as liquid ; third, from its latent heat ; fourth, from its critical 

 temperature and pressure ; fifth, from its surface-tension : 

 all the methods being afterwards proved to give accordant 

 results for a large number of compounds. 



8. The fifth or capillary method treated in greater detail, 

 with digressions on the Brownian movement and molecular 

 distances. 



9. Establishment on theoretical grounds of Eotvos's rela- 

 tion between surface-tension and molecular domain (volume). 



10. Tabulation for a large number of bodies of the product 

 of the square of the molecular mass by the virial constant 

 determined by several methods, and verification thereby of 

 the general principles preceding. 



11. Establishment of the law connecting the virial constant 



