480 
MR. B. H. GRIFFITHS OH THE VALUE OF 
cWA {1 -kd^-e + 
clt “ JEM (1 + I 6^6) 
6. In the section on resistance in Table XVI. we have collected the values of 
li 
-- T-—Z - - -T- at the mean temperature of each range. The value of n, the 
1 — k {Vy — a -\- p) 
number of Clark cells used, is given with each experiment. Substituting their values 
we obtain the time of rising 1° C. with unit resistance and one Clark cell, or 
E' 
3M(1 + / - d) = T 
(12). 
This gives column 10 of Table XXXVII. 
7. The results of all the experiments were then meaned and plotted, the columns 
headed “ Mean ” and “ From curve ” in Tables XL. and XLI. giving the results. 
From these smoothed curves the values of the required constants were calculated 
thus :— 
8. If W.^ is the water-equivalent of the calorimeter, and f and g are the tem¬ 
perature coefficients of the specific heat of water and of the calorimeter respectively, 
and suffixes written to W, I, T, denote the values of these quantities for different 
weights of water, then from (12) we obtain 
and 
where 
(W, + WJ (1 + = tG 
1- 
I (W, + W.) (1 + kep^e) = tJ 
/W, + ,j\N. 
C- Wi-fW, 
and 
_ /W, 
2 W, + Mb 
( 13 ) . 
(14) . 
Hence, subtracting equations (13), we get 
or 
I (w, - Wj) (1 +/», -D) = n - T, 
(w, - wo (1 +f0, - d) = - T,,„ 
i(w, - wo(i = n. - T,, 
j 
( 15 ). 
and 
