688 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



20 



30 



40 



50 



80 



60 70 



Temperatures. 



Figure 7. 



K, ~ 0.0645 [1 - 0.00159 (t - 20)]. 



Note : Results marked + are preliminary. 



90 



too 



110 



Discussion of Results. 



From the plot of the value of K we find the average deviation of the 

 results to he less than 0.15 per cent, — the maximum variation being 



A 100 ^20 



a little over 1 per cent. The coefficient = "'"" " - as obtained 



80 A. 20 



from these results is found to be 0.00159. 



A point to be noticed is that the amount of energy supplied to the 

 interior of the shell as represented by the watts was never the same, and 



