28 Proceedings of the Royal Society of Edinburgh. [Sess. 
IV. Dr Eccles and Professor Maurain’s Experimental Results. 
Dr Eccles plots the induction changes due to superposed oscillations 
produced by single minute sparks against cyclic field as abscissae. 
The curves are discontinuous in the same way that the curves obtained 
by plotting dl/dH against cyclic field are discontinuous at the cyclic 
extremes. My previous paper showed that the curves representing the 
effect of vibrations or oscillations superposed at all points of a normal 
loop form a continuous loop. In this respect Professor Maurain’s 
experiments and those of others agree with my own. It was also pointed 
out that the neutral points are thrust towards the cyclic extremes the 
less the intensity of the vibrations or oscillations. The present paper 
shows how very close the neutral points may approximate the cyclic 
extremes, but they can only vanish there when the effect of vibrations or 
oscillations superposed at the cyclic extremes is zero. 
My own experiments, however, differ from those of Eccles to a less 
extent than those of Maurain, who varies the conditions of the former’s 
experiments. Eccles superposes oscillations of the same intensity through- 
out upon hysteresis loops of various amplitudes. Maurain superposes 
oscillations of four different intensities upon the same loop throughout. 
One of the results is that “ plus les oscillations agissantes sont faibles , plus 
le maximum de leur action seloigne du maximum de la courbe des 
distances D et se rapproche du maximum de dl/dH.” This is clearly shown 
in fig. 3 of the paper, as also that the maximum of each curve is thrust 
from the maximum of dl/dH in the direction of the vertical axis the 
stronger the intensity of the oscillations. Maurain continues: — “ En 
somme, la consideration de la distance D a la courbe d’ aimantation 
stable , qui permet dejd de prevoir le sens de V action des oscillations, est 
importante egalement pour prevoir Vintensite de cette action, et cela 
d’autant plus qui les oscillations sont plus intenses .” 
In fact, Maurain’s curves (fig. 3) show (1) that dl/dH becomes a more 
and more important factor than the distance D in determining the 
maximum of the curves due to oscillations the weaker their intensity ; and, 
conversely, (2) that the distance D becomes the more important factor the 
stronger their intensity. Thus it is that Eccles’ results obtained with 
minute sparks approximate more nearly to Maurain’s result (1) with 
“ tres faibles ” oscillations than to result (2) when the intensities are 
taken stronger and stronger. They approximate still more closely to 
my own results with the weakest vibrations or oscillations used, because 
under these conditions, with the neutral points thrust in my case close 
