24 
MR. J. REGINALD ASHWORTH: 
For steady values of a and I this latter method of constructing magnets is to be 
preferred, and with further experimental experience even the small coefficient here 
exhil)ited might yet he reduced ; the high intensity, too, which is yielded by this 
method of producing approximately zero coefficients is another advantage. The 
magnetic moment of these magnets was about 227 each for a weight of 2-59 grammes. 
It will be noticed that, in the magnets which have been constructed to have 
nearly zero coefficients liy cutting them to a suitable dimension ratio, there is a 
tendency for the positive coelficient to grow less and become negative as the intensity 
declines, and vice vevsd. This is in accord with the results already found for the 
relation of the hot and cold curves, where larger and smaller values of the intensities 
than those corresponding to the intersection of the curves give positive and negative 
coefficients respectively. 
Indeed, in any magnet we should expect a change of intensity to produce a change 
of the coefficient if the latter is dependent on the disposition of the hot and cold 
curves of magnetisation, and hence the decay of magnetism with the laj^se of time, or 
the increment of magnetism which takes place on remagnetisation, will tend to alter 
the magnitude of the temperature coefficient. In the latter case such effects have 
been noticed.* 
* 
Jhle CiiKEE, ‘Roy. Soc. Rroc.,’ vol. 65, p. 375. 
