410 Proceedings of the Royal Society of Edinburgh. [Sess. 
to cool, it remained non-magnetic down to the ordinary temperature of 
the room. 
It will be seen from Diagram III. that in the case of the particular 
Heusler alloys under test the cooling curve never rises to the heating curve. 
Diagram IY. 
Thus heating above the critical temperature results in the magnetic quality 
being to some extent destroyed. The effect of continued heating and 
subsequent cooling is shown in Diagram IY. A specimen was placed within 
the coil and an I-H curve obtained. By means of the furnace the tempera- 
ture was gradually raised to 520° C. (above the critical temperature) ; the 
