Temperature on the Specific Heat of Aniline* 65 



and therefore in the length of the ordinate, would produce 

 its full effect, and might be appreciable, but as regards the 

 determination of the specific heat by the method of differences 

 it is almost certainly negligible. It would be represented by 



2 1 -j where p 1 and p 2 are the values of p when 



the masses of the liquid are M x and M 2 ; and since 



Pi(M 1 S 1 +w l )= P2 QlL 2 $ 1 +w l ), 



the limit of error is given by the expression 



^(Ms-mq e,-e N 



MA+t*! n 2 ' 



AT ^ 1 v S^Ma-MJ . Li 



JNow the value ot ,; a — - — — in these experiments was 



about ;j, hence we get j^ . — — ^ — as the expression for the 



dd 

 error, and this would in no case amount to y^oo °f ~J~~ • 



etc 



I assume, therefore, that the values of —7^ given by the 



experiments are sufficiently approximate. 



If C5 is the value, in degrees C. of the air-thermometer, of 

 the temperature difference equivalent to 1 centim. of the 

 bridge-wire*, then 



d0K Hi x Cfi 

 x 



dt e 2 



gives the rise per second in degrees C. with unit resistance 

 and unit potential-difference. 



The reciprocal of the quantity thus found gives us T, the 

 time of rising 1°, when E = l and R=l. 



Now T 



Let the value of T be T x when M is M 1? and T 2 when M 

 is M 2 . 



Then we get a « ; T 1 



* See p. 54, supra. 

 Phil Mag. S. 5. Vol. 39. No. 236. Jan. 1895. F 



