332 MR. E. H. GRIFFITHS ON THE LATENT 
In the same manner (Appendix II., Experiments V. and VI.) it was found that 
at temperature 30° 
(d0,/dt)s. = 15035, and (d6,/dt), = ‘002348 (formula B, supra), 

hence 
(dO,/dt), 2848 
GUD, = ial 
and at 30° 
R, = 10°348, 
therefore 
1:4342? 
H= 10348 x 4198 — 04735 thermal gram per sec. 
therefore 
Q, (rate 5°300) = 04735 x 1405 = 006654 thermal gram. 
Now assuming (A) and (B), it follows that 7*/Q, is constant, and we can deduce 
that if 7, be any rate and 5°300 the standard rate 
At temp. 40°°1, Q, = -004659'-- (7,4 — 789) <x "0000059" 2) 2 3 a(@): 
At temp. 30°-0, Q, = -006654 + (rt — 789) x 0000084. . . . (D). 
I performed one stirring experiment at 50° and two at 20° and I give the results 
only, as the values of Q, at these temperatures are not required for the reduction of 
the L experiments described in this paper. I was unable (for want of time) to prove 
how nearly the effect of changes of rate could be expressed in the same manner as at 
30° and 40°, but as the rate was nearly 5:3, the corrections introduced by the reduction 
to rate 5°3 were very small. The results were of use, as on plotting the curve for 
the values of Q, at the four different temperatures it showed no signs of irregularity, 
and thus gave additional strength to the determinations at 30° and 40°. The values 
are as follows :— 
At temp. 50°, Q, = -00235 + (rf — 789) x 0000030 . . . . (E). 
At temp. 20°, Q, = 00768 + (m4 — 789) x 0000098 . . . . (F). 
The values of Q, at 30° and 40° receive a certain amount of support from the 
preliminary experiments referred to in Section VII. Although my results by that 
method varied considerably amongst themselves, the mean of five experiments at 40° 
gave ‘00000802 gram of water evaporated per 1 sec. by the stirring after reduction 
to rate 5°38, and the mean of four experiments at 30° gave ‘00001137 gram of H,O 
evaporated per sec. at the same rate. 
