588 Proceedings of Royal Society of Edinburgh. [sess. 
the lower end a mirror was attached, and in this mirror the 
reflected image of a millimetre scale was viewed through a 
telescope, the scale and telescope being both at a distance of 256 
cm. from the mirror. The circular magnetization was produced by 
an axial current passed along a rubber-covered wire which threaded 
the tube 20 times. This sheaf of wires really passed through a 
glass tube placed loosely inside the nickel tube, so that there was 
no fear of the wires coming in contact with the nickel. 
Table II. — Tivists in Nickel Tube under the influence of circular 
(H') and longitudinal (H) magnetizing forces. 
IT . 
H . 
Twist . 
H ' 
H . 
Twist . 
1-23 
132-5 
•4 + 10-6 
5-74 
131 
3-2 + 10-6 
80-1 
*8 „ 
84 
4-4 „ 
64-4 
2-4 „ 
61 
6 „ 
26 
1-4 „ 
36 
4-8 „ 
24 
3-2 ,, 
2-4 
159 
1-6 + 10- 6 
132 
1-4 ,, 
6-3 
157 
3-4 + 10- 6 
106 
1-6 „ 
131 
3-8 „ 
80 
2-2 „ 
105 
4-6 ,, 
53 
3-0 5 , 
79 
5-0 „ 
27 
2-0 „ 
53 
6*3 ,, 
37 
6-2 ,, 
4-33 
160 
2-4 + 10- 6 
27 
5-8 „ 
133 
3-2 „ 
16 
2-8 „ 
106 
3-8 ,, 
— 
80 
4*0 „ 
15-8 
159 
6-8 + 10-6 
53 
4-4 ,, 
132 
7’8 „ 
37 
4-7 „ 
106 
8-8 „ 
27 
39 „ 
80 
11*0 ,, 
16 
2-8 „ 
53 
11-7 „ 
32 
9*4 ,, 
10-9 
65 
8-2 + 10- 6 
21 
6-0 ,, 
44 
8-8 ,, 
10 
2-8 ,, 
22 
6*4 „ 
In the preceding Table of results H is the longitudinally 
magnetizing field produced by the current in the vertical mag- 
netizing coil, H' is the circularly magnetizing field acting on the 
thin wall of the tube, and due to the axial current. The “ twist ” 
is the angular displacement of the mirror divided by the length of 
the tube. The observed deflections were very small, never 
exceeding 2 of the millimetre divisions of the scale, so that the 
