742 
PROFESSOR F. G. BAILY ON THE HYSTERESIS OF 
during the process the hysteresis is too high. On breaking and remaking the circuit 
after a sudden reduction in the current, the deflexion of the armature, previously 
lower than the normal, rises to a value higher than the normal and then drops to its 
normal value, showing that by breaking the circuit, the regular arrangement is 
completely disturbed. 
Professor Ewing in his book (“ Magnetism in Iron,” &c.) mentions that rapid makes 
and breaks increase the permeability, but increase still more the residual magnetism, 
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but he does not give the hysteresis effect, which may or may not have been increased. 
This is clearly a case of “ accommodation.” When, however, the current is reversed, 
the increased amount of combinations renders the iron less permeable with more 
“coercive force” necessary, and therefore with presumably more hysteresis. The 
result does not seem to agree very well with that of Tomlinson’s, 
In the rotating field it is possible that rapid makes and breaks tend to disarrange 
the symmetrical arrangement produced by continued rotation, and to increase the 
