OF ARTS AND SCIENCES. 



323 



the constancy of k no longer tenable. Thus it appears that the march 

 of q is within the errors of I, and hence it has no meaning. Cf. § 9. 

 It follows, in general, therefore, that the results obtained iu measure- 

 ments of the compressibility of thymol are not inconsistent with the 

 calorimetric data ; and it has thus been brought out, inasmuch as the 

 dissociation energy is not large relative to the expansion energy, that 

 the premises of § 8 are sustained. 



18. Energy and Volume. — I have finally to touch upon the data 

 obtained for specific heat, and their bearing on the purely thermal 

 energy of thymol. It is interesting in the first place to compare the 

 heat absorbed per unit of volume increase in the solid state, the liquid 

 state, and during the change of state from solid to liquid. This has 

 been done in the following table. 



TABLE VL — Volume Relations of Thermal Capacity. 



Thus it appears that the energy expended per unit of volume in- 

 crement is in marked degree greater for the solid than for the liquid 

 state, and is greater in both of these states than during the inter- 

 mediate fusion. 



14. Sufficient data are now in hand for the computation of the 

 specific heat at constant volume of thymol. Applying the well known 

 thermodynamic relations (cf. Clausius, Chap. VIII., § 5) at 29°, 

 Table V. shows (d Vejdp) = 66/10^- in terms of dynes per square 

 centimeter and atmospheric pressure nearly. Under the same con- 

 ditions {d Vpidd) = 801 /1 0« from Table I. Hence the specific heat 

 at constant volume C„ is, from Table III., 



0, = .506 - ((29 + 273)/42 x 10'') ((801)2/66) = .436, 



or about .86 of the specific heat at constant pressure C^ = 506. 



