1 8 CALORIFIC POWER OF FUELS. 



The total elevation of temperature is 



20.676 18.460 = 2.216, 



and the correction is 



20.676 20.620 = 0.056 for five minutes, 

 or 0.011 for one minute. 



Then 



2.216 : O.on = 0.620 : 0.0031 

 2.216 : o.on = 1. 660 : 0.0083 

 2.216 : o.on = 2.145 : 0.0107 

 2.216 : o.on = 2.215 : O.oiio 

 2.216 : o.on = 2.218 : o.ouo 



Total 0.0441 



There is then 0.0441 to be added to the difference, 2.2 16, 

 increasing it to 2.260, which is the corrected difference of the 

 bath temperature, from which the heat of combustion of the 

 substance burnt in the calorimeter is calculated. 



Regnault and Pfaundler's formula is 



Atn Ato + K(tn to) ; 

 in which 



Atn = ascertained variation of temperature from the heat- 

 ing and cooling of the calorimeter for one 

 minute; 



Ato = variation at the beginning; 



tn to = loss or gain during the total time of the test; 

 n = number of minutes of test. 



Using the above numbers, 



o.on 



K=- -^ = 0.00496. 

 2.216 



