diurnal variation of the magnetic needle , &c. 315 
corresponding to these different angular positions of the 
heated point, are inserted in the columns over which are 
indicated the points on the plate which were successively 
heated ; the deviations in the first column of each set being 
due to the particular angular positions of the heated point 
when that point approached the compass through the north ; 
those in the second, when it approached through the south ; 
and those in the third, the means of these two, and which are 
considered as the deviations due to the several positions of the 
heated point, had that point preserved its mean temperature 
throughout the revolution of the plate. 
0 the heated point. 
180 the heated point. 
90 the heated point. 
270 the heated point. 
Deviations. 
Deviations. 
Deviations. 
Deviations. 
c3 
<u 
s ^ 
the points on the 
When the points on the 
When the points on the 
When the points on the 
<D — 
~ .2 
brought under the 
plate brought under the 
plate brought under the 
plate brought under the 
“o .2 
ass in 
the 
compass in the 
compass in 
the 
compass in the 
SO 
ect 
Reverse 
Mean. 
Direct 
Reverse 
Direct 
Reverse 
Direct 
Reverse 
er. 
order. 
order. 
order. 
order. 
order. 
order. 
order. 
1 
O ' 
O / 
O / 
0 / 
O , 
O / 
O / 
O 6 
O 9 
0 E 
0 30 E 
2 i ; E 
0 45 E 
0 30 w 
0 15 E 
i 30 E 
0 30 w 
0 52 E 
0 30 w 
1 30 W 
1 22 W 
0 30 E 
0 W 
12 30 W 
12 30 w 
22 30 w 
17 45 w 
20 07 w 
23 30 W 
16 45 w 
20 07 W 
15 00 W 
17 00 w 
16 00 w 
17 1 1 E 
0 w 
23 30 W 
28 00 w 
34 00 W 
25 45 Wi 
29 52 w 
34 3 ° w 
24 30 W 
29 30 W 
26 30 w 
26 30 w 
26 30 w 
28 28 E 
0 w 
26 30 w 
29 15 w 
31 00 w 
25 30 W 
28 15 w 
30 30 w 
25 00 w 
27 45 w 
26 30 w 
13 00 W 
29 45 w 
28 4c E 
0 w 
7 00 W 
5 15 w 
1 30 E 
1 45 w 
0 07 w 
5 15 E 
0 15 E 
2 45 E 
4 00 W 
8 45 W 
6 22 W 
2 15 W 
0 E 
33 00 E 
27 30 E 
23 30 E 
31 30 E 
27 30 E 
26 00 E 
33 00 E 
29 30 E 
1 6 15 E 
34 3 ° E 
25 22 E 
27 28 E 
0 E 
35 3 ° E 
28 00 E 
24 30 E 
36 00 E 
30 15 E 
25 00 E 
34 3 ° E 
2 9 45 E 
1 6 30 E 
38 30 E 
27 30 E 
28 52 E 
0 E 
25 00 E 
18 30 E 
16 30 E 
23 30 E 
20 00 E 
1 6 30 E 
25 00 E 
20 45 E 
9 15 E 
23 30 E 
16 22 E 
18 54 E 
0 E 
4 3° E 
0 30 E 
0 15 E 
1 00 E 
2 30 E 
0 30 W 
3 00 W 
In comparing the mean results when the different points of 
the plate were heated, it is to be considered that minute accu- 
racy could not be attained, either in applying the lamp to the 
precise point indicated, or exactly to the middle point between 
the two surfaces of the plate ; and that the angular distances 
