RESEARCHES IN MAGNETISM. 
589 
In this, the first, stage of loading, and with this small amount of stress, on gave 
increase, and off gave decrease of magnetism. 
Then the loading was continued, with the result that the application of load up to 
2 kilos, carried the magnetism through a maximum down to a value below the initial 
value, while unloading left it permanently raised : — 
Load. 
Magnetometer. 
0 
291 
1 
292 
2 
290 
1 
292 
0 
293 
And another application and removal gave :— 
Load. 
Magnetometer. 
0 
293 
1 
292 
2 
290 
1 
291 
0 
293 
Here, then, the effects having become cyclic, on gives fall, and off gives rise of 
magnetism, and the presence of hysteresis is quite distinct. This last action is 
repeated for all loads up to the limit of elasticity. 
The cycles of loading and unloading were now progressively extended, by going 
1 kilo, higher each time, but still keeping well within the limit of elasticity. The 
resulting magnetometer readings showed that, besides the alternate changes (on giving 
fall, and off giving rise of magnetism), there was a slight gradual reduction of the 
magnetism, due, doubtless, to some hardening of the metal; for the wire, although 
not visibly stretched, could scarcely fail to be permanently affected by the application 
of even these moderate amounts of load :— 
4 g 
mdccclxxxv. 
