316 



PROCEEDINGS OP THE AMERICAN ACADEMY 



Measurements of thermal expansion made with a variety of methods 

 gave me the data of Table I. They have been conveniently put in 

 the form of an equation (Mendeleeff), r = t'o /l —kd, where v is 

 the specific volume of thymol at 6° C, and k is all but constant as to 

 temperature. 



The discrepancies here observed are easily explained, being in part 

 due to unavoidable insulficiencies of the methods, and in part to the 

 special properties of thymol. The numbers in Italics correspond to 

 the conditions under which the calorimetry must be done, and are 

 therefore selected. 



It will be seen that at zero the difference of specific volumes solid- 

 li<]uid is about .0485 c.c, whereas at 50° the same difference has in- 

 creased to .07G0 c.c, an increase of more than 50%. This cannot be 

 regarded as a mere differential. Indeed, the relations are such that 

 the curves if prolonged intersect at about — 100% after which the 

 volume of the solid exceeds tliat of the li(|uid. In other work * I 

 referred to the same point as the transitional temperature, and inferred 

 it from the tendency of the volume lag to vanish when temperature is 

 decreased below a certain value. The new evidence in favor of a 

 continuous jiassage of the normal type of fusion into the ice type is 

 noteworthy. Solidification contraction decreases with temperature at 

 a rate very much more rapid than tlie coetRcients of expansion. 



G. Latent Heat. — A general survey of my best results for latent 

 heat (X) are given in the following table, for the intervals of temper- 

 ature specified. 



TABLE II. — Latent Heat of Thymol varying with Temperature. 



* Am. Journal, Vol. XLII. p. 145, 1891. 



