392 
MR. E. H. GRIFFITHS ON THE VALUE OF 
difference in temperature of the wire and the water, appeared, therefore, to have heen 
overcome. This conclusion, however, led to the loss of many weeks’ work, and was 
the cause of much disappointment and delay. In the summer of 1891 we commenced 
a series of direct determinations of J, the arrangement of the apparatus being very 
nearly the same as that of 1892. Our coil consisted of about 30 inches of the above 
wire, H, which w'as first annealed at a temperature of about 200 ° C. in an atmosphere 
of CO 3 . The fine white silk covering was allowed to remain, and it was painted wuth 
Mr. Laurie’s, amber varnish.* 
The resistance of this coil, and of the leads from it to the calorimeter lid 'svhen in 
situ and immersed in rapidly stirred water, is shown in the following table. 
Table III. 
Temperatures . 
14° 
16° 
18° 
20° 
to 
to 
0 
24° 
August 21, 1891 . . 
R=10-5214 
10-5220 
10-5223 
10-5225 
10-5226 
10-.5225 
Eesistance of the coil at temperature 14° C., on different dates. 
Aug. 22 
. 
10-5228 
„ 23, 
11 A.M. 
10-5275 
„ 23, 
1 1 P.M. 
10-5299 
„ 24 
• . • . 
10-5342 
25 
• « . • 
10-5398 
27, 
before exp. 
J 3 
10-5559 ; 
after 
exp. Jg . 
• • « • • 
10-5600 
„ 28, 
>5 n 
Jr 
10-5570 ; 
9'9 
ii Jr • 
10-5632 
„ 29, 
J? J) 
J 5 
10-5618 ; 
99 
■>•> J 5 
10-5696 
,, 30, 
9J 
Jc« 
10-5760 ; 
9J 
Jca • 
10-5860 
„ 31, 
9 9 9) 
Jt 
10-5867 : 
99 
„ Jt . 
10-5962 
„ 31, 
9 9 9 9 
Jg4 
10-5953 ; 
99 
Jes • 
10-5977 
Sept 1, 
10 A.M. . 
. 
10-5968 ; 
(some current passed) 11 p.m. 
10-5982 
The resistance of the ware at different temperatures was also ascertained in the 
observations taken August 21 to 25. 
It is unnecessary to give the resistance at temperatures other than 14° C., since the 
resulting curves are all parallel to the one on August 21 . The alteration caused by 
a rise of 10 ° C. being only 1 in 10 , 000 , the steady diurnal rise in the resistance (at 
the same temperature) amounts to nearly 1 in 500 in the above interval of time. We 
trusted that this might be a result of the annealing, and that the wure would assume a 
stable condition in course of time. 
* Mr. Laurie was so kind as to allow us to have a bottle of this varnisli prepared by bimself; for par¬ 
ticulars concerning this varnish, see ‘ Proceedings Cambi’idge Phil. Soc.,’ vol. 7, part 2, p. 52. 
