SYSTEM NAPHTHALENE-CHLOEOBENZENE-PHENOL, ETC. 11 



benzene and water we see that the former has a rapidity of 

 cooling twice as great as the latter. The heat capacity of the 

 vessel etc. was 3.5 while the heat capacity of 20 c.c. chlorobenzene 

 was 22x0.33 (see below). Hence the total heat capacity was: 



22x0.33 + 3.5 = 10.8. 



The total heat capacity of the vessel with 20 c.c. of water was : 



20 X L + 3.5 =23..5. 



The ratio of these heat capacities is : 



23..5 



10.8 



= 2.17. 



As might be expected the heat capacity is inversely proportional 

 to the rate of cooling, other conditions being equal. We there- 

 fore calculated the loss of heat during observation according to 

 this conclusion. We determined in the first place the heat 

 capacity of the vessel, the stirrer, etc. The result was as follows : 



where 



t = the temperature at which the determination was made, 

 Jl = the temperature elevation due to the electric current, 



+ the cooling during the observation, 

 V — the volume of water to be warmed, 

 H. Q = the heat quantity determined by means of the iodine- 

 voltameter, 



