of Vapours to Mariotte and Gay-Lussac's Law. 301 



The specific volumes of the three vapours examined are found, 

 according to the principles of the mechanical theory of heat, laid 

 down in Zeuner's Grundzuge, 1866, where the values of u given 

 in Tables 3. b, 5. b, and 7. b, multiplied by the values of a given 

 page 288, determine the specific volumes for each vapour. 

 The values of u given there are calculated on the basis of Reg- 

 nault's formula? for tension and the heats of evaporation com- 

 municated by Regnault. In order to render possible a compa- 

 rison of the specific volumes of perfectly saturated vapour thus 

 obtained with those derived from the relation p ] v l — const. Va + 1, 

 I have calculated these last from Regnault' s tensions, using the 

 theoretical vapour-densities, and at the same time I have given 

 the volumes which result according to the old view when the 

 vapours are supposed to follow the laws of Mariotte and Gay- 

 Lussac. The foundations for these last have thus been built upon 

 Regnault's tensions and the theoretical vapour-densities. 



Table V. — Specific volumes of perfectly saturated vapour. 



Alcohol. 





a. 



b. 



c. 



Temperature. 



According to 



Calculated from 



On the old as- 





Zeuner. 



p 1 i) l =ci V a+t. 



sumption. 



10° 



17-3294 



15-7730 



157859 



30 



57316 



50354 



5-2142 



50 



21345 



1-8567 



19851 



70 



0-8822 



0-7775 



0-8566 



100 



0-2863 



0-2585 



0-2970 



120 



01538 



01394 



01643 



140 



00902 



00814 



00984 



Chloroform. 



10 



1-4698 



1-4644 



1-4656 



30 



0-6413 



0-6150 



0-6368 



50 



03143 



0-2938 



0-3141 



70 



01693 



01554 



01712 



100 



00774 



00696 



0-0799 



120 



0-0498 



0-0442 



0-0521 



140 



0-0339 



0-0296 



00358 



Bisulphide of Carbon. 



10 



11719 



1-1660 



1-1669 



30 



0-5662 



0-5508 



0-5703 



50 



0-3005 



0-2884 



0-3084 



70 



01720 



0-1641 



0*1808 



100 



00834 



0-0799 



00918 



120 



00547 



00530 



00625 



140 



00374 



0-03G8 



00444 



