544 
Proceedings of Royal Society of Edinburgh. [sess. 
The Molecular Condition of Iron demagnetised 
by various Methods, By James Russell. 
(Read July 20, 1903.) 
(Abstract.) 
The demagnetisation of iron by decreasing reversals secures a 
molecular condition such that there is perfect symmetry to subse- 
quent applications of either a positive or negative magnetising 
force (H). In a former communication * it was shown that this 
symmetry is uni-directional. It is symmetry to the directional 
force (ab) used in the demagnetising process. During the early 
stages of induction iron is more permeable to a reapplication of a 
magnetising force in the same direction ( + or - ) as that used in 
the immediately preceding demagnetising process, than it is to a 
force ( + or - ) at right angles to that used in the immediately 
preceding demagnetising process. The hypothesis was advanced 
that on the completion of this process, a preponderance of the 
molecules would point towards an equatorial belt at right angles 
to ab. If H makes an angle other than zero with ab , the number 
of molecules lying in the most advantageous position, i.e., equa- 
torially, is reduced, and the pull becomes less and less as the 
angle approximates to 90°. 
Various deductions are now made from this hypothesis. If the 
angle between these two forces be 0° or 90°, there will obviously 
be no induction component at right angles to itself on H being 
applied. When ab makes an angle other than 0° or 90° with H 
(say 45°), the molecular rotations involved are illustrated by means 
of diagrams which project the axes of the molecules upon the 
surface of a sphere. It is seen that the application of H ought 
(First) To develop an induction component at right angles to 
itself, which will tend to disappear as saturation values are 
reached, and which ought 
* “ Magnetic Shielding in Hollow Iron Cylinders,” Trans. Roy. Soc. Edin., 
vol. xl. p. 649. 
