32 Heats of Vaporization of Liquids. 



In Exp. II. 



m = 0*3659 gramme. 



M 1= 14-698 grs. M 2 =18'887 grs. 



Y 1= 5-359 volts. V 2 = 6-799 volts. 



.-. L = 96*80 calories. .-. L = 95*58 calories. 



Mean result of four experiments : L = 91*53 cal. 



The value of L for benzene is known to be 94*4 cal.* 

 The agreement obtained here is not of course sufficient to 

 make the results of any direct value : the difficulty lay in so 

 adjusting the strength of the current that it should be strong 

 enough to make the benzene boil tranquilly, and yet not 

 be too strong for the voltameter . This might easily be 

 arranged, and it is quite possible that fairly accurate absolute 

 measurements might thus be made with comparative ease. 



Appendix. 



Eegarding the purity of the liquids employed. 



ELexane was lent by Prof. Sydney Young. 



Methyl Alcohol was supplied by Baird and Tatlock, and 

 guaranteed free from acetone. It was distilled with sodium 

 until it boiled constantly at 64'95 at 761*9 mm. 



Formic Acid (see also Comptes Rendus, cxxii. p. 1333, 1896) 

 was supplied by Kahlbaum, and was subjected to fractional 

 distillation until a portion was obtained boiling at 100° to 

 100°'5 at 751-2 mm. 



Methyl Iodide was prepared by the author, dried with 

 calcium chloride, and distilled, using a fractionator like that 

 described by Young and Thomas (Chem. INews, Ixxi. p. 177): 

 b.pt. 43°*4 at 769*8 mm. 



Ethyl Iodide was similarly prepared, and distilled in the 

 last instance from P 2 5 : b.pt. 72°-8-72°-9 at 765*5 mm. 



Ethyl Bromide was dried with calcium chloride and phos- 

 phoric anhydride : b.pt. 39°-75-38*°95 at 765*5 nnn. 



Chloroform was obtained from Baird and Tatlock : it was 

 washed with water, then with concentrated sulphuric acid, 

 then with w T ater again ; left to stand with phosphoric anhy- 

 dride for some hours, and distilled with the fractionator : 

 b.pt. 61°*7-61°*8 at 760*0 mm. 



Carbon Tetrachloride was fractionated from P 2 0^ : b.pt. 

 76°-7-76°-8 at 759*5 mm. 



* Griffiths and Marshall, Phil. Mag., January 1896. 



