1912-13.] Electrical Resistance and Magnetization of Nickel. 211 
Here the longitudinal field is 47*4, and the transverse field is 170. Each 
of these alone produces much the same amount of change of resistance, 
the one positive and the other negative. When the cyclic longitudinal 
field is superposed upon the steady transverse field, the effect of the former, 
though still positive, is much less than when there is no maintained 
transverse field. We might reasonably enough express this by saying 
that the transverse field, which by itself produces a decrease in the 
resistance, continues when maintained to impose a kind of molecular 
restraint against an influence which would by itself increase the resistance. 
But in the neighbouring experiment, V. 4, the effect of the longitudinal 
field when superposed upon the steadily maintained transverse field is 
a further decrease of resistance. There is not merely a restraining 
action against the normal influence of the cyclic field ; there is a 
change in the method of molecular yielding, the superposed longi- 
tudinal field having the same general effect as an additional transverse 
field. 
An examination of the whole set of experiments shows that when the 
nickel strip is magnetized transversely by a force not exceeding 250 or 
thereabouts, the change of resistance due to the superposition of a given 
longitudinal magnetic field is markedly less than when the longitudinal 
field acts alone. For a transverse field somewhere in the neighbourhood 
of 250 or a little lower, there is no further resistance change when a 
longitudinal field is superposed. As the maintained transverse field is 
increased above this critical value, the effect of the superposed longitudinal 
field is to decrease the resistance, not to increase it. And this decrease 
increases with the longitudinal field. 
It should be noted that the change of resistance due to the superposed 
longitudinal field is measured from the resistance which the material has 
under the influence of the steady transverse field. Now this transverse 
field has already produced a decrease of resistance or increase of conductance 
in a direction perpendicular to its lines of force. When along this direction 
of increased conductance the lines of force of a second field are made to act, 
the conductance of the nickel is decreased or increased according as the 
steadily acting transverse field is less or greater than a particular critical 
value. The further removed the transverse field is from this critical value, 
the greater numerically is the change of conductance associated with the 
superposed longitudinal field. 
Consider now the effect of a steadily maintained longitudinal field upon 
the change of resistance due to a cyclically applied transverse field. In the 
case V. 3 already cited we see that the transverse field which acting alone 
