﻿Rate of Evolution of Heat by Orangite. 



IS' 



column B gives the mean deflexion attained, C gives the 

 heat generated electrically, D the increase in deflexion due 

 to the heater obtained by subtracting the mean of the 

 deflexions for the preceding and following period from 

 the deflexion for the given period. 



Column E is obtained by dividing C by D and hence 

 gives the number of calories per hour necessary to cause a 

 deflexion of one scale-division. 



A. 

 AB .. 



B. 



Scale- 

 divisions. 

 .. 26-1 



C. 

 Calories 

 per hour. 







D. 



Scale- 

 divisions. 



E. 



Calories 

 per hour 



BC .. 



. . 29-3 



0-0170 



3-65 



0-00466 



CD .. 



. . 25-25 











DE .. 



. . 41-3 



0-0992 



20-0 



0-00496 



EF .. 



. . 23-4 











The two figures in column E agree tolerably well, but as 

 the rise for period BC was so small we may assign more 

 weight to the value found for the period DE and assume 

 that each scale-division correspcnds to the emission of 

 O0049 calorie per hour. It will be found that this value 

 was confirmed by the later experiments. 



Hence for the period AB the heat evolution per gram 

 of orangite is found to be 



26-1x0-0049 .._ in _ 5 ' , 

 — — — = 2b*b x 10 ° calorie per hour, 



similarly for the periods CD and EF we obtain 



25*8 x 10" 5 and 23 9 X 10~ 5 calorie per hour 



respectively. 



These values are extraordinarily high, being four times as 

 high as the figures obtained for pitchblende. The diminution 

 observed seemed to indicate that some temporary source of 

 heat was in operation, so the whole calorimeter was laid 

 aside unopened for nearly a year. 



Second Series of Experiments. 



Eleven months after the sealing up of the orangite a new 

 determination was begun. For about a month various 

 arrangements of the ice vessel were tried with a view to 

 obtaining a more uniform temperature but as they were all 

 failures the original arrangement was finally reverted to. 

 During the month which immediately preceded the period 



