1908-9.] Vibrational Neutral Points in Magnetised Iron. 33 
diagram XI. In the descending curve A R the long arrow represents the 
theoretical shift of the neutral points towards A the weaker the vibrational 
intensity. According to the above deductions, the shift of the neutral points 
is towards the cyclic extreme where the last reversal of field change took 
place, and consequently in the ascending curve R A it will be towards R the 
weaker the vibrational intensity. In the two branches of this little loop, 
therefore, between which the induction does not differ greatly, the shift of 
the neutral points will be in opposite directions, as indicated by the arrows, 
and is therefore independent of the values either of the field or of the 
induction. 
Similarly, in all the other ascending curves the shift of the neutral 
points will be towards the negative field extremes of their respective loops 
the weaker the intensity of the vibrations, until finally the last of the series 
A l R x A becomes symmetrical with A R A 1? the curve descending from the 
positive extreme. 
F urther, the ascending branches of these and all other intermediate loops 
cut either the vertical or horizontal axis, or both, at all points in a positive 
direction ; while the descending branches, which coincide with one another, 
cut the vertical and horizontal axes only at their positive and negative 
extremes respectively. Hence the direction of the induction change due to 
vibrations superposed at all points of the axes included within the large 
VOL. xxix. 3 
