50 
Proceedings of the Royal Society of Edinburgh. [Sess. 
positive, and the reversible effect which is always negative. At low values 
of field and induction the former predominates, at high values the latter. 
Successive positive induction changes may be obtained with successive 
VALUES OF B. AT FORTIETH "OFF” OF LOAD 
ORDINATES, CHANGES OF B.-ABSCISSAE, 1st TO 40th “ONS" AND "OFFS OF LOAD. 
increments of load, but this possibility is limited with fields increasing 
from zero to a very narrow range (fig. VI.). In general, the second and 
further increments of load will either produce no effect or lower the 
induction (fig. VIII.). Successive “ ons ” and “ offs,” however, augment the 
