400 
Mr, Christie on the magnetism oj 
Table of the values oJ and 0' — 9 , computed from the equations (5^), (6^) 
compared with their mean observed values in Table B. 
X 
V 
e, 
6' — 0, 
Observed. 
Computed. 
Difference. 
Observed. 
Computed. 
^^Difference. 
Observed. 
Computed. 
Difference . 
0 
0 
• / // 
+ 50 28 
0 / 1 / 
+ S 3 38 
° / // 
+ 3 10 
0 / // 
— 50 28 
0 11/ 
— 53 38 
f // 
— 3 10 
0 / „ 
1 40 56 
0 / // 
I 47 16 
/ // 
+ 6 20 
10 
4 30 50 
4 46 12 
+ 15 23 
2 54 52 
3 05 20 
+ 10 28 
I 35 58 
I 40 S 3 
+ 4 55 
20 
7 38 os 
7 59 10 
+ 21 05 
6 15 27 
6 35 29 
+ 20 02 
I 22 38 
I 23 41 
+ I 03 
30 
10 07 50 
10 06 20 
— I 30 
9 03 12 
9 OS 40 
+ 2 28 
I 04 38 
I 00 40 
- 3 58 
40 
50 
60 
II 02 12 
10 44 55 
9 12 10 
10 55 28 
lo 29 02 
8 52 55 
— 6 44 
— *5 53 
— 19 15 
10 23 37 
10 32 35 
9 24 40 
10 22 47 
10 21 56 
9 08 05 
— 0 50 
— 10 39 
— 16 35 
38 35 
12 20 
— . 12 30 
32 4 > 
07 06 
— 15 10 
— 5 54 
— 5 14 
— 2 40 
70 
0 33 52 
6 19 59 
— *3 53 
7 06 20 
6 52 26 
— *3 54 
— 32 28 
— 32 27 
4- 0 01 
80 
3 *o 50 
3 07 34 
— 3 16 
3 56 00 
3 SI 32 
— 4 28 
— 45 10 
— 43 58 
-j- I 12 
90 
— 24 49 
— 23 36 
+ I 13 
+ 24 49 
+ 23 36 
— I 13 
— 49 38 
— 47 12 
+ 2 26 
The differences here between the observed and computed 
values of and are not greater than might possibly arise 
from slight errors in the adjustments of the plate and com- 
pass in the several positions, and their agreement is I think 
sufficiently near to prove that the principle which I have 
assumed, namely, that the attraction of the mass of the iron 
may be referred to its centre, and on which the most consi- 
derable of the terms in the formulae depend, will account for 
the phaenomena independent of the rotation of the iron. Al- 
though the differences between the observed and computed 
values of or of the deviation due to rotation^ are abso- 
lutely less, yet they are relatively greater ; but their general 
agreement is such, that we can have little doubt of the devi- 
ations due to the rotation of the iron being, in all cases, nearly 
the same as would arise from such a polarising of the iron, 
as we have supposed. We shall however form a better esti- 
mate of the agreement between the results of the theory and 
observation, by eliminating - from the equations (5) and 
