312 
Proceedings of Royal Society of Edinburgh. [sess. 
On Superposed Magnetic Inductions in Iron. 
By James Russell. 
(Read July 7 and 21, 1902.) 
[Abstract.) 
A communication was made to this Society on February 3, 1902, 
on “Magnetic Shielding in Hollow Iron Cylinders.” At an early 
stage of this investigation, and when dealing with more magnetis- 
ing forces than that due to the transverse field acting upon the, 
shield, the subject of cross magnetisation necessarily came to the 
front. This paper deals, First , with the superposition of two 
magnetising forces at right angles to each other, and the co- 
ordination of the two components of the resultant magnetic 
induction, under the various conditions of field superposition ; 
and Second , with the magnetic ceolotropy of demagnetised iron. 
The same hollow iron cylinders were used as in the shielding 
experiments. 
I. Of the two magnetising forces at right angles to each other, 
let Hj be the force first acting, H 2 the force superposed. Each 
force acting alone produces the normal B-H induction curve. Let 
Bj and B 2 he the two components of the resultant induction in the 
directions of H x and II 9 respectively. 
When H 2 is superposed upon a pre-existing induction due to Hj, 
the B x component o the resultant induction always lies above the 
B 2 component. Repeated reversals of H 2 accentuate this result; 
B x is further increased ; and concurrently with this, B 2 is further 
lowered. For low fields, the Bj component is considerably above 
the normal induction curve, but as the fields are increased a point 
is reached where the curves cross, the B x component then falling 
below the normal curve. Also the superposition of H 2 lowers the 
B 2 component below the normal induction curve, ivith this excep- 
tion , that at low values of H x the superposition of the second force 
H 2 increases the B 2 component above the normal induction curve. 
This is, however, a relatively small effect. 
