18 
MR. J. RFXimALD ASHWORTH: 
magnitude of the temperature coefficient may be inferred from the disposition of the 
hot and cold curves of magnetisation. This is still further confirmed by reference to 
Diagram V., where the temperature coefficient of drawn steel, for both ascending 
Diagram V. 
The relation of temperature coefficients (a) and (a^) and permanent change of magnetism (fi) to 
residual intensity. 
and descending values of magnetisation, is plotted against the residual intensities 
left finally after heating and cooling. The broken curve traced underneath is the 
change of residual magnetism per unit per degree of temperature calculated from 
curves of residual magnetism when the wire was at 16° and when it was at 100°. 
This is marked (as it corresponds to the temperature coefficient of suscejotibility for 
residual magnetism), and is traced for both ascending and descending intensities. 
The distinctive features of one curve are reproduced in the other, although, as might 
be expected, owing to irreversible changes, the curves are not an accurate fit. Thus, 
the zero coefficient experimentally found is displaced largely to the left of the zero 
position in the calculated curve. 
If the iron curves, traced in the same way, are examined, the distinctive features 
of the one will be found also reproduced in the other, but with a large displacement 
