510 Br. S. Young on the Boiling -points of 



The constants for the formula D = A+a£ are : — 



Substance. A. a. 



Methyl Formate . . . *5025 - -0007155 



Methyl Acetate . . . -4839 - -0006740 



Ethyl Formate . . . -4759 -'0006490 



Ethyl Acetate . . . . '4644 -'0006250 



Methyl Propionate . . "4721 -'0006210 



The critical densities of the five esters, obtained by the 

 method of diameters, are : — 



Methyl Formate '3494 



Methvl Acetate '3255 



Ethyl" Formate '3232 



Ethyl Acetate -3081 



Methyl Propionate '3123 



From the differences between the observed and calculated 

 mean densities it may be concluded that, though there may 

 be in some cases a slight indication of curvature, it is far too 

 small to affect the determination of the critical densities of 

 these substances. 



LIX . On the Boiling-points of different Liquids at Equal 

 Pressures. By Sydney Young, J3.Sc, Professor of Che- 

 mistry, University College, Bristol*. 



T^ARLY in the present year, M. E. Colot (Compt. Rend. 

 cxiv. p. 653) described a relation between the boiling- 

 points of any two liquids under equal pressures, which may 

 be shortly described as follows. 



If t and 6 are the temperatures of the two substances at 

 any pressure, then 



t = A0 + B, 



where A and B are constants depending on the nature of the 

 liquids. 



The constants given by M. Colot refer to Centigrade tem- 

 peratures, but for the purpose of this paper it is better to 

 employ absolute temperatures. In this case A remains un- 

 altered, but B has a different value. 



There are certain cases in which B = (for absolute 

 temperatures), and the equation then becomes 



t = A6 or g=A. 

 * Communicated by the Physical Society : read October 28, 1892. 



