398 ME. W. HOPKIXS OX THE COXSTErCTIOX OF A XEW CAiOEIMETEE 
successively in this equation, the values of 6, f, and^ above given as mean values in the 
series of experiments I., II., and III., and for Q we substitute the corresponding mean 
values of Ha — tliG increase of temperature of the calorimeter due to the radiation 
upon its lower surface. The quantity of heat represented by Q will thus be measured 
numerically by the number of Faheexheit degrees by which the temperature of the 
water in the instrument is augmented. This numerical value may be represented by Q*. 
Its proper numerical value vrill be introduced hereafter. 
After tedious numerical calculation, in which I feel satisfied there is no material error, 
the following values of m were derived from the three series respectively. 
I. t= 47°’7 (C.), m.= l||=-77; 
II. «=I0I°-6 (C.), m,= ^ =-80; 
Q.QQ 
III. m3=^=-T8; 
Mean value of wi=mo=‘T83. 
I have above stated the various corrections which ought to be applied to the values 
of Fg — Fi, or of Q in the last formula. They wiF lead to a corrected value of nig, which 
we may now proceed to find. These corrections are as follows : — 
(1) Correction due to the influence of the external air. — It will be remarked that the 
difference between this temperature and 6, that of the calorimeter in the preceding expe- 
riments, is very small. The correction is inappreciable. 
(2) The correction due to the central orifice in the glass disc (art. 8). — In the formula 
of that article 
^=•006. 
The ratio - is found from the experiments which determine the whole radiation in air 
from the surfaces of mercury and glass to be somewhat different for different tempe- 
ratures. It may be taken as folloAvs in the mean of each of the preceding series : — 
In I. - = ‘6 nearly. 
In II. - = ‘7 nearly, 
'UT 
In III. - = '8 nearly. 
Hence the formula (3.) of aid. 8 becomes 
In I. Q''=Q, {I+-0064(I--6)} 
= I-52{I + -0025}, 
In II. Q»=4-I6{I + -00I9}, 
111 III. Q«=8-88{I + -00I3}. 
