454 
MR. E. H. GRIFFITHS OH THE VALUE OF 
when the pressure falls below '50 millim. is remarkable; but a reference to Botto:mley’s 
paper will' show that the curve given by him is of a similar type, although the 
critical point is at a higher pressure arid the bend in the curve is less sharp. 
Fig. 8. 
Although all the observations on the “non-electrical supply” have been brought 
together in this section for the purposes of comparison, they were not taken con¬ 
tinuously but in groups. Each group of observations was used for the reduction of 
J experiments performed at the same time and on the same weight. The stirring 
experiments were usually performed during the daytime, the corresponding J experi¬ 
ments in the evening, and it was rarely that two sets of J observations were taken 
on the same day. Throughout the whole of the experiments J 1 to 34, as also their 
corresponding stirring experiments, the surrounding temperature was maintained at 
300 E = 19-260 a* 
If 02 — temperature of calorimeter, then — 19"260) p gives the rise or fall in 
temperature per second due to radiation, &c., hence cr + — 19‘260) p, gives the 
rise in temperature per second due to the whole “ non-electrical ” supply. As 
previously pointed out (see note, p. 411) we proposed to reduce the numbers obtained 
from our J experiments at certain fixed temperatures and the following Table gives 
the changes in temperature per 1 second, due to the “ non-electrical ” supply at these 
points. The numbers were obtained from large-scale curves, but can be calculated 
from the values of cr and p given in this section. 
* In previous years we Lad performed several pairs of experiments in wliicli the outside temperatui’e 
was, in one case at the bottom, and in the other at the top, of our range. By “ meaning ” the reciprocals 
of the times of rising 1°, the effect of radiation, &c., could he eliminated. We hoped to repeat these 
experiments this year, but want of time prevented our doing so. 
