292 



K. Tsuruta on the Alleged Sign of 



of pressure on the variation of e p is negligible. Though our 

 presumption in favour of this is strong, I thought, it well to 

 obtain an estimate, if not an evaluation, of the amount of 

 that influence. By the fundamental principles of thermo- 

 dynamics 



OlCp 



■T. 



■dp - -"dT' 

 and by integration along an isothermal we obtain 



,=/(T)-tJ|^ 



dp. 



Therefore, the question under consideration depends upon 

 the second term of the right-hand member. 

 Grimaldi * proposes the following formula, 



Vq 



■~"A/jC —~ /^2 ? 



to represent his results on the compressibility of ether above 

 mentioned, where v is the volume at 0°, and k^ k% are con- 

 stants for a given pressure. The numbers in the first three 

 columns of the following table are due to Grimaldi : — 



p=900cm., *! = 0-001440, Ar 2 =0'00000243. 



t. 



v/v 

 obs. 



v/v 

 calc. 



v. 

 Grimaldi. 



v. 

 Eamsay & Young. 



0° 



1-00000 



rooooo 



1-3550 



1-3550 



20 



103113 



1-03068 



1-3972 



1-3975 



40 



1-06505 



1-06551 



1-4431 



1-4445 



60 



1-10475 



1-10515 



1-4969 



1-4963 



80 



1-15035 



1-15041 



1-5687 



1-5648 



100 



1-20250 



1-20236 



1-6294 



1-6330 



The last two columns give the volumes of ether in cubic 

 centimetres, those of the first set being obtained by multi- 

 plying the observed relative volumes by 1-3550, which is 

 approximately the volume at 0° and under the pressure of 

 900 cm., and those of the second set being interpolated from 

 my diagram of isothermals drawn according to the measure- 

 ments of Ramsay and Young. Quite a good agreement will, 



* Grimaldi, Zeitsch. fur phys. Chemie, Bd. i. p. 556. 



