1903-4.] On the Molecular Condition of Demagnetised Nickel. 309 
Note on the Molecular Condition of Nickel (and Iron) 
demagnetised by decreasing Reversals. By James 
Russell. 
(Read July 18, 1904.) 
In a former communication * it has been shown that iron 
demagnetised by decreasing reversals of a directional force ab , 
develops an induction component at right angles to the sub- 
sequent magnetising force H, when the angle 9 between these two 
forces is other than 0° and 90°. This component after reaching a 
maximum tends to disappear as saturation values are reached. 
It has now been found that these transverse induction effects 
also exist in nickel. 
The curves for nickel resemble those for iron in the following 
respects : — 
[First) They change sign either if the direction of H he re- 
versed, or if ab be rotated through an angle of 90° ; 
{Second) Their maxima are sharpest when 6 = 45 ° ; and 
{Third) They vanish in the horizontal axis when 0 = 0° and 90°. 
The curves for nickel differ from those for iron in the following 
respects : — 
{First) The smallness of the transverse induction is extreme. 
When 0 — 45°, the nickel curves reach a maximum of about 
13 C.G.S. units only. In iron, under the same conditions, the 
maximum attained is equal to fully 230 C.G.S. units. In order 
therefore to compare by superposition the curves obtained for 
nickel and iron, the nickel ordinates require to he increased 
eighteen times. 
{Second) If ab be rotated so that 9 is gradually reduced from 
45° to 0°, and the values of H he not too small, the curves are 
relatively increased in value to an extent greater than the corre- 
sponding curves for iron. Further, if 9 be not too small, the 45° 
maximum is even exceeded. 
* “The Molecular Condition of Iron demagnetised by various Methods,” 
Proceedings Roy. Soc. Edin . , vol. xxiv. p. 544. 
