232 MESSRS. W. R. BOUSFIELP AND W. ERIC BOUSFIELD 



observations in Table VI. gives the value S 16 = 01965. This value is used to obtain 

 the values of S. from the values S M *. The last columns of the table show the values 

 of S,' calculated from the formula So' = <ri949 + <r000090, and also the differences 

 between observed and calculated values. 



The experimental values of S * are set out in fig. 9. 



The mean capacity of the calorimeter employed for the main research was found to 



.-.I5-5 joules between 13 C. and 54'5 C. To apply the above result to this we 



must note that this capacity includes not only the glass, but also about 170 gr. of 



mercury. The specific heat of mercury diminishes with rise of temperature from 

 0'0335 at C. to 0'0328 at 80 C. by a straight-line law. Taking this into account, 



the expression 



C/= 578-3 + 0-255 (0+00 



gives the mean capacity in joules per degree of the calorimeter between any two 

 temperatures 0, tf. It will be found that between the limits 13 C. and 54 "5 C. the 

 value given by the formula is the experimentally found value 595 "5, while for the end 

 values of the capacity at C. and 80 C. the ratio of the values agrees with those 

 derived from our experimental values for glass and from the figures quoted for 

 mercury. 



Subjoined are the resulting values of the mean-heat capacity of the calorimeter for 

 the various intervals which are hereafter dealt with : 



Mean capacity 



Interval. in joules 



per degree. 



to 13 581-6. 



13 27 588-5. 



27 40 595-4. 



40 55 G02'5. 



13 55 595'G. 



55 73 GIO'9. 



55 80 6127. 



