12 
MR. J. REGINALD ASHWORTH: 
immediately rose to 400, more than three times the former amount, and the subsequent 
alternations of temperature slowly augmented the intensity until a final value was 
approached at 477 ; the coefficient then was + 0-000731. Raised another step by a 
force of 19-1 units, the intensity became 724, and, after heating and cooling a few 
times, it rose to 993 ; the coefficient now was + 0-000466. And lastly, with a force 
of 76-5, the intensity was 1311 initially, and after heating and cooling 1316, the 
coefficient being + 0-000206. The enormous growth of magnetism under changes of 
temperature in the earlier stages of magnetisation, and the insignificant increment in 
the final state, concurrently with the large coefficient when the susceptibility is large 
and its diminution as the susceptibility becomes less, are the features here principally 
to notice. 
Applying next a small negative force of — 7-19 units, the intensity dropped finally 
to 745, and the coefficient was then + 0-000229 ; and it might be anticqmted from 
the position of the point of intersection of the hot and cold curves already examined, 
that a slightly larger demagnetising force ought to annul the positive coefficient, and 
that a still larger demagnetising force ought to yield a negative coefficient. 
A force of — 11-23 units was next applied and maintained, which, while less than 
the coercive force for the material hot or cold, was greater than the force at the point 
where the curves cross. With this force we get the following resrdt 
Intensity. 
Cold. 
Hot. 
+ G18 
- 
+ 259 
+ 227 
+ 134 
+ 145 
1 
j- Here the south pole was uj^warcls. 
1 
+ 69 
1 
+ 65 
1 
I 
+ 8 
J 
+ 10 
Mao-netism reyei‘.sed. 
CO 
CO 
1 
- 34 
- 80 
- 74 
- 116 
> The north i^ole is now upwards. 
- 107 
- 151 
- 141 
Here it is evident that the force applied has been too large to allow a cyclic state 
to be established before reversal of the magnetism sets in, yet, in accordance with 
anticipation, up to the point where the original magnetism is entirely removed the 
hot value of the intensity intermediate between any two cold values is alv-ays less 
