No. 7.] HORIZONTAL INTENSITY. 99 
According to this, we obtain the difference of the means: 
a—b 
For magnet V . . . + 0°:00062 
“ ni Es ea 000056 
From the 24th May to the 26th September, 1895, the vibration box was 
placed upon the ordinary stand of the apparatus, and the revolver, as usual, 
between the legs of the stand. The following determinations of H, for the 
purpose of ascertaining the influence of the revolver in this position, were 
made: 
Magn. V Magn. VI 
a b a b 
The revolver ; The revolver | The revolver | The revolver 
in its place laid aside | in its place laid aside 
11" 17” a.m. 
11 48 0°04991 
12 7Tp.m. 
12 32 0'04984 
22 p. m. 0°05227 
0'05278 
0°05274 
0°05274 
0°05248 
0:05248 
0°05140 
0°05122 
0°05153 
0°05148 
005125 0°05133 0°05253 
According to this, we obtain: 
a—b 
For magnet V . . . —0°-00008 
VI. . . —0:00031 
” ” 
When the ice hut was taken into use on the 26th September, 1895, the 
revolver, as stated in the introduction on page 9, was placed on the ice at 
a distance of 3 metres to the north of the stand of the instrument. From 
