no Mr. Christie on the mutual action of 
the torsions as before : the numbers in the third column are 
deduced from the observed deviations by substituting them 
in the expression. 
Arc of torsion = 6610. Sin deviation; 
and the values of a, or the torsion of the wire which is equi- 
valent to the force with which the ring urged the magnets at 
different distances, are found by adding the deviation to the 
preceding arc of torsion. 
Table IX. 
e section of 
>of the mae- 
, c , &c. 
> 111 
r d 
QJ . 
§j? 
CJ >- 
cn <U> 
oj *5 
C , 
licli is equi- 
iation. 
lich is cqui- 
with which 
uagnels, or 
Values of M determined from 
different combinations of 
a , a , a , a , &c. 
11 111 IV V 
Values of t J 
determined 
from 
M = 46 63 
and the se- 
parate ob- 
servations. 
-o « 
Ctf 
2 a; 0 
E g 
<y .5 
*•8 
<D 
i j- i 0) 
* 8 2 
CJ -Z -G 
1 8 
O 
Combinations. 
V alues of M. 
Distance of the 
the ring from th 
nets, or \ alues 
rS & 
0 2 
G <D 
.2 3 
■> ^ 
<D 
ft 
s ~ 
<u 0 
£ G 
0 Jd 
c 5 
.2 > 
0 
H 
Torsion of the w 
valent to the 
the ring urges 
value of a. 
! Value of a 
n 
a 
11 
a 
u 
a 
11 
a 
a 
IV 
a 
V 
a 
VI 
a 
47 828 
47*497 
47-525 
47-075 
c m 2*2 c6 
11 
o°36' 
69*2 
69*8 
a =*119694 
n 
a 
111 
Vll 
a 
V 
45*860 
•4918 
c m 1*756 
811 
x 23*5 
160*5 
161*9 
a =‘078592 
111 
a 
111 
a 
VI 
4 6 '347 
•5812 
c — 1*506 
IV 
2 20 
269 1 
27^4 
a hi *060701 
IV 
a 
in 
a 
Vll 
45-779 
•5624 
c = 1*256 
V 
4 o6 ’5 
473-6 
477-7 
\ =-045753 
a 
IV 
a 
VI 
46*859 
•5559 
c n: i*oo6 
VI 
7 3 ° 
862*8 
870*3 
« V1 — " 0 33^97 
a 
IV 
a 
Vll 
45-875 
•5686 
c =0*756 
Vll 
*5 2 7‘5 
1761*8 
1777-3 
a =*02 '1720 
Vll 
a 
V 
a 
Vll 
45*659 
•5345 
Mean values 
46 630 
• 549 * 
If we compare the torsions in the fourth column, which are 
equivalent to the force with which the ring by its rotation 
urges the magnets, with the mean torsions before obtained, 
which represent the force with which the magnets urge the 
ring when revolving horizontally under it, we shall find the 
