94 
Mr. Christie on the mutual action of 
the times in which the ring completed successive revolutions, 
and in which it began to turn in the direction of unscrewing 
were noted; and also the number of revolutions and the 
degrees marked by the index when this took place. The 
same was done when the magnets revolved in the direction 
of unscrewing, and the means taken. The results obtained at 
different distances are tabulated below, where a, 6, 0,, t, tt, 
represent the same quantities as before. 
Table I. 
0 <l> 
0 ^ 
*.3 3 
W 
1 the ring 
re retro- 
“is 
S -9 ” 
r- — CO fi 
'f ^ 1 
0 cu 
'H ^ 
*3 a> 
.3 C 5 
fi (IJ 
, P c 
0* ^ 
e> “S 
c-E " 
rArc of torsion when 
[ came to rest befoi 
1^ grading. 
•* 
These are = ^ 6| 
was less than 360 ®, 
the mean of the val 
when fij was greater tl 
CO ^ 
5 - = 
Y 
Values of 9 , 
Valties of * 
2’5 inches 
0 
2275 
11*375 
2-0 
S »-5 
2575 
1*5 
I 44.-0 
72*00 
1-25 
278*0 
139-00 
O) 
I'OO 
581 5 
289*18 
(2) 
075 
* 344-5 
706 25 
( 3 ) 
0*50 
* 
p 
00 
1982*5 
Distance of the middle-^ 
section of the ring from 1 _ 
the upper surfaces of the f — 
magnets - -J 
I *0 inch. 
0*75 inch. 
0*5 inch. 
9 
t 
9 
t 
9 
t 
9 
t 
vers. TT.— 
a— j 
vers. TT.— 
h 
t 
vers. TT. — 
h 
0 
‘ I 
2 
360 
720 
1080 
sec. 
183*0 
287*6 
sec. 
10275 
15975 
■7 T 
748-6 
718*4 
685-5 
sec, 
59*25 
88*5 
110M25 
T “2 1 • 7 C 
2188*3 
.i 3 U bo 
fe V- c 
0 *c 
2038*7 
1983*4 
1961*3 
1960*7 
1942*4 
f r 
D 
4 . 
1440 
1800 
C 
* J* / J 
151*62 
170*37 
190*75 
212*5 
236*25 
269*25 
0 u ^ 
c ® 
7 
8 
2160 
2520 
z88o 
. 
. 
s ^ 
.2 Ci 
</> 0 
0 c -ti 
H 'o wS j 
9 
lio 
3240 
3600 
•••••« 
. 
. 
1928*0 
1916*5 
Values of and a 
= |0. 
315*0 
290*75 
315-0 
672*5 
320*25 
1926*5 
Mean values of ce, 
(1) 
289*18 
(2) 
70625 
(3) 
1982*5 
• When the copper ring was at the distance *5 inch from the magnets, its outer 
circumference was at the distance of less than ‘25 inch from the inner circumference 
of the graduated ring, on which the deviations and revolutions of the copper ring 
were measured, and which rested upon the screen; but this produced no effect, at 
least that was sensible even at this small distance; for after removing the graduated 
ring, the times of completing the several revolutions of the copper ring, and like¬ 
wise the whole arc of torsion before it came to rest, were found to be as nearly as 
possible the same as they were previous to the removal. 
