500 Mr. Christie on the magnetism developed in 
same was the case at revolutions (unscrew). So that 
although the effects* were greatly diminished by connecting 
the poles, they were by no means destroyed. 
The magnets were now placed over each other, first with 
poles of a contrary name, and then with those of the same 
name contiguous. 
No. of 
revolutions. 
Poles of a contrary name 
contiguous. 
No. of 
revolutions. 
Poles of the same name 
contiguous. 
Screw. 
Unscrew. 
Screw. 
Unscrew. 
Time. 
Time. 
Time. 
Time. 
1 
2 
2 tV 
At 2-j^ (sc 
torsion of the 
of the magnet 
m. s. 
I 48 
3 20 
3 so 
rew) and 2^ 
wire was eq 
s. 
m. s. 
1 32 
2 40 
/Rev. \ 
( 45 
(unscrew) the 
ual to the force 
1 
2 
3 
4 
5 
6 
s. 
21 
30 
36 
42 
47 
51 
s. 
21 
29 
34 
39 
44 
48 
So that although the upper magnet was nearer to the disk, 
by its own thickness, than in the 4th experiment, the effect 
when poles of contrary name contiguous was not half what it 
was when they were connected by the iron. 
A thick copper plate 8 inches in diameter and i inch thick, 
was placed on the axis of rapid rotation, its plane horizontal. 
A thin copper disk 4 inches diameter, and weighing 23.5 
dwts. was very delicately suspended over it by a fine brass 
wire (No. 37), with a paper screen between the plate and the 
disk. The distance between the surfaces of the plate and 
disk -/q inch. The plate being put in rapid rotation, no sen- 
sible effect was produced on the disk. 
A bar magnet was placed on the screen under the disk : 
still no effect produced by the rotation. 
