specific and Latent Heat of Vaporization. 9 



other impurity, perhaps sulphur, seems to lower the latent 

 heat, a value as low as 76 having been obtained with impure 

 substance. 



CORRECTION TO VACUUM. 



Let n be the true weight of the nickel, 

 ,( y, <i (' " " " platinum, 

 « ^ u ii " " " carbon bisulphide. 



The volume of the nickel and platinum at the air tempera- 

 ture may be taken as 



M + ^ = 3-03cc.; 

 8.9 21.5 



that of the brass weights as 



3156=. 3.69 cc. 



The actual weight of the nickel and platinum is therefore 

 «+/ = 31.06- (3.69- 3-03)0.001213, 



0001213 being the density of air at mean temperature and 

 normal pressure. The volume of the nickel and platinum at 

 46° has been assumed as 3-33 cc, that of 0929 grams of CS 

 is o 76 cc, if the density is calculated from Hirn's formula 

 for the expansion of this liquid. The volume of the platmum 

 weights added in the other scale-pan is 0.04 cc. 



203 



