Latent Heat of Evaporation of Benzene. 27 



19. Tables B. 



(The numbers of the columns are similar to those in the 

 corresponding tables of Paper W, where full particulars of 

 the reductions are given.) 



(ne\ ^ X t 

 Col. XV. The value of Q,*»= R xj' » where ' is th& 

 potential-difference of 1 Clark cell, at the 

 temperature given in Col. X. {supra). The 

 values of R Y will be found in Table 111. p. 17, 

 and, as previously explained, the value of 

 J = 4*199 (see section 6, p. 8). 

 XVI. The value of Q s deduced from Col. VI. by means 



of Table IV. p. 19. 

 XVII. The value of Q s £ s , the " stirring supply," from 

 Cols. V. and XIV, 

 XVIII. The term tq=C 9 {(0 o '-0o")-(d'-d")} from 

 Cols. VII., VIIL, and IX. 

 XIX. The sum of Cols. XV., XVII., and XVIII., that 

 is, the total thermal grams (2) required for the 

 evaporation of M grms. of benzene. 

 XX. The mean tank temperature (0 O ) of the experi- 

 ment, expressed in the nitrogen scale. 



XXI. The value of L=^. 



Remarks on Experiments at 50°. 



Exp. XIX. a. " Mistake in switching off current, did not 

 do so till #! had risen so far that d" could not be obtained by 

 means of galvanometer-swing. Had to readjust contact on 

 bridge at close of experiment. Decided to regard experi- 

 ment as a failure and repeat it/' 



The experiment is included in the table to show that even 

 the large resulting value of the term Xq ( — 18*64) has but a 

 small effect on the value of L, which differs from the mean at 

 this temperature by less than 1 in 400. This value for 

 L (98*90) should, however, certainly not influence our final 

 conclusions. 



Exp. XXIII. — " Mistake in connecting with vacuum, re- 

 duced pressure far below right amount, hence could not 

 obtain proper thermal balance throughout experiment." 



Conclusion. 

 When O =5O*O14, L=99*14. 



