38 
Proceedings of the Royal Society of Edinburgh. [Sess. 
II. — The Effect of Load and Vibrations upon Magnetism 
in Nickel. By James Russell. 
(MS. received April 13, 1908. Head November 18, 1907, and March 2, 1908. Q 
CONTENTS. 
Objects of Investigation . 
Apparatus and Methods . 
Cyclic Fields 
Cyclic Residual Magnetisation 1 
Increasing Fields . 
Discussion and Summary . 
page 38 
55 
39 
Data, page 40 ; Results, „ 
46 • 
55 55 ’ 5 5 5 5 
48 • 
5 > 55 ? 55 55 
• * * 55 
43 
47 
49 
52 
The initial irreversible effects of applying or of removing stress resemble 
those produced by vibrations, although these processes “ may be conducted 
in such a way that no actual vibration takes place.” * Ewing has investi- 
gated the initial effects of tension in iron,-)- Cree the initial effects of 
pressure in cobalt.^ In iron and cobalt, tension and pressure respectively 
increase the induction before the Villari reversal in both metals is reached. 
Vibrations also in non-cyclic fields increase induction. Consequently in 
low fields the initial irreversible and final reversible effects of tension and 
pressure in iron and cobalt respectively augment each other. In nickel, on 
the other hand, the irreversible and reversible effects of tension must 
oppose each other ; the latter effect lowering the induction at all stages of 
field increasing from zero.§ In Ewing and Cowan’s paper, however, no 
mention is made of any initial effects tending towards induction increase. 
Nickel has therefore been selected as the subject of these experiments, 
and annealed nickel, because in this condition the effects of mechanical 
vibrations are large, and in comparison with quenched nickel entirely 
normal in character. || The irreversible and reversible effects of load with 
and without permanently acting mechanical vibrations are investigated 
(1) in fields increasing from zero; (2) in cyclic fields; and (3) in zero field 
with what may be called cyclic residual magnetisation, which will be 
defined later. To differentiate these effects the loads used must be small. 
* Magnetic Induction in Iron , Ewing, 3rd edition, p. 216. 
t Phil. Trans., 1885, p. 603. % Phil. Trans., 1890, p. 329. 
§ Lord Kelvin, “Electro-Dynamic Qualities of Metals,” part vii., Phil. Trans., 1879; 
Reprint of Papers, vol. ii., pp. 332-407. “Magnetic Qualities of Nickel,” Ewing and 
Cowan, Phil. Trans., 1888, pp. 325-333. 
|| “ The Superposition of Mechanical Vibrations upon Magnetisation,” etc., Trans. Roy. 
Soc. Edin., xlv. p. 491. 
