Boiling-points and Molecular Volumes of Liquids. 423 



There are very few actual determinations of latent heat by 

 which this conclusion can be tested. In the cases, however, 

 of methyl chloride and iodide and ethyl chloride and iodide, 

 the values found at atmospheric boiling-points agree fairly 

 well with the theory. But it should be remembered that such 

 determinations are not to be relied on as more than near 

 approximations to the truth (compare Ramsay and Young, 

 Phil Mag. Dec. 1885). 



Formula. 



L.* 



M. 



T. 



M.L 



T ' 



OH,Cl 



969 

 46-1 



50-34 

 141-50 



249-3 

 315-8 



19-57 

 20-66 



CH 3 I 





(XH-Cl 



100-1 

 469 



64-31 

 155-47 



285-5 

 344-3 



22-55 

 21-18 



C 2 H 5 I 





Melbourne, 18th August, 1890. 



XL VI. On the Relation between the Boiling-points, Molecular 

 Volumes, and Chemical Characters of Liquids. By Sydney 

 Young, D.Sc, Professor of Chemistry, University College, 

 Bristol f. 



THE appearance of the preceding very interesting paper 

 under the above title by Professor Masson has induced 

 me to bring forward the following considerations at a some- 

 what earlier period and in a probably less complete state than 

 I had originally intended. 



In his dissertation ' On the Continuity of the Gaseous and 

 Liquid States ; Van der Waals has proposed the following 

 generalizations as applicable to all substances : — " If two 

 substances be compared at absolute temperatures which are 

 proportional to their absolute critical temperatures, their 

 vapour-pressures will be proportional to the critical pressures, 

 and their specific volumes (both of liquid and saturated 

 vapour) will be proportional to their critical volumes." 



Assuming the truth of these relations, we may calculate the 



* The figures in this column are taken from Ramsay and Young's 

 paper (loc. cit.), where the authorities are not given ; except that for 

 methyl chloride, which is quoted from J. Chappuis (Chem. Soc. Abstr., 

 1887,' p. 627). 



f Communicated by the Author. 



