458 PROFESSOR A. SCHUSTER AND MR. W. GANNON ON A 
Our final value is 
4'1804 on the mercury scale of hard French glass, 
J = 107 X < 4:1905 on the nitrogen scale, 
4:1917 on the hydrogen scale, 
at a temperature of 19°'1. 
This result depends on the assumption that the electrochemical equivalent of silver 
is 0'001118, and that our standard Clark cell had an electromotive force of 
1°4340 (1 — at — 15) volts, 
where « = ‘000814 + ‘000007 (¢ — 15) as given by Kau eE (‘ Zeitschrift fiir Instru- 
mentenkunde,’ vol. 13, p. 310, 1893). GLAZEBROOK and SKINNER’S coefficient refers 
to a mean temperature of 7°°5, and is identical with the above at that temperature. 
Discussion of Results. 
The comparison of the results of different observers will be facilitated by Table XIII., 
in which we compare ergs with the foot-pound at Greenwich and the kilogram-metre 
at Paris. 





Tape XIII. 
| i Foot-pounds at Kilogram-metres at 
Ergs x 107. Gee, is Paris. 
4-160 772°83 424-07 
4-165 773°76 424:58 
4-170 77468 4.25°09 
41765 77561 425°60 
| 4-180 77654 426711 
| 4-185 | W747 4.26°62 
4-190 77840 427:13 
4-195 779:33 427-64 
4-200 780 °25 428:°15 
4-205 78119 4.28°66 
4210 78214 429°17 

This table has been calculated on the assumption that g at Paris is equal to 980:96, 
and at Greenwich equal to 981:24. 
We have prepared another table (XIV.) which will give at any temperature the 
correction of an interval measured on our mercury thermometer to an interval measured 
on the nitrogen and hydrogen thermometers. This table has been calculated with the 
help of the equation given by Cuappurs for the correction to the thermometer made 
of French hard glass. 

