Temperature on the Specific Heat of Aniline. 6 7 



was 9*10 revolutions per second, for the remaining experi- 

 ments 5*00. A considerable number of experiments gave 

 tr 2 = 800,000 approximately, where r is the rate per second, 

 and t the time of rising 1 centim. of the bridge-wire. The 



correction to the normal rate therefore is ~ )( nnn , where r is 

 the normal and r x the observed rate. > 



As the stirring rarely departed much from the normal this 

 correction was always small, it in no case exceeded "00006, 

 and rarely exceeded '00002 ; and as the values of tr 2 given 

 by the stirring experiments did not differ by more than 

 1 part in 50, the correction is sufficiently close. 



IV. The correction consequent on changes in the tempera- 

 ture of the bridge-wire. This is given with sufficient accuracy 

 by the expression 



JQ 



^X{1 + -00016(^-59)}, 



X being measured by a Fahrenheit thermometer. 



V. The correction for the temperature of the Clark cells. 

 Assuming Lord Rayleigh's temperature-coefficient '00077, 



cJ6 

 we get -~{i + *OO154(0—15H ; for the rate of rise varies 

 as E 2 . dt 



VI. The subsequent operations are simplified if some arbi- 



trary value is assigned to R', and the consequent value of -~ 



for that value of R/ ascertained. As the resistance of the coil 

 increased from about 8*45 to 8'6 ohms as 6 X increased from 

 15° to 50° C, it was found convenient to take 8 5 ohms as 



the arbitrary resistance. The correction is —- x tj-t* 



at o'D 



The true value of K 1? however, is not that obtained by 

 merely taking the resistance in the usual manner with a 

 small current. I have in paper J, pp. 404-7, published 

 a full account of a method of finding the increase in W 

 due to an increase in the potential-difference of 1, 2, &c. 

 Clark cells. 



The increase, with this coil, was carefully determined, with 

 the following results*: — 



* I have to thank Mr. F. H. Neville, Fellow of Sidney College, Cam- 

 bridge, for his kindness in assisting me in this somewhat troublesome 

 determination. 



F 2 



