10 



ART. 12. H. HIROBE : ON THE FUSION SURFACES OF THE 



Q = the quantity of electricity passed, 

 t = the time during which the current was passed, 

 0.238 = the electric equivalent of the heat. 



Q was determined by means of the iodine voltametei-,^^ and the 

 time was read to a second with an ordinary watch. 



The apparatus employed for the determination was the same 

 as that described later on. In such an arrangement the cooling 

 effect is considerable and must of course be taken into account. 

 In Fig. 5 the relation between the temperature elevation above 

 that of thermal equilibrium and the rate of cooling for one 

 minute is given for water and chlorobenzene. As is to be seen 

 from curves 1 and 2 (Fig. 5) the rapidity of cooling is almost 

 independent of the quantity of the liquid. This is perhaps due 

 to the fiict that the greater the amount of the liquid, the greater 

 is the surface exposed. By comparing the curves for cliloro- 



0.10° 0.20° 0.30° 



— > Rate of cooling ïov one minute. 



Curve 1. 20 c.c. water. 

 Curve 2. 40 c.c. water. 

 Curve 3. 20 c.c. chlorbenzene. 



Fiff. 5. 



0.40° 



0.50° 



1) Pliys. Zeit, 6, 579-581, (1905). 



