194 Proceedings of the Royal Society of Edinburgh. [[Sess. 
the maximum, and then diminished down to zero, the same procedure being 
followed as in the preceding experiments. This was repeated with weights 
of 1*2, 1*5, and 1*8 kilos., the results being shown in the graphs. These 
results are, in all cases, what was obtained after the cyclically steady state 
had been reached. 
On examining the graphs, the first thing to be noticed is the diminution 
in the modulus as the weight is increased, and also the fact that the 
hysteresis at the same time becomes gradually smaller and smaller. 
In figs. 5 and 6 are shown the results of those experiments in which 
the current was kept constant while the load was varied. An examination 
of them shows that as the current is increased the modulus at first increases 
and then diminishes. We also notice that when the field is weak the 
effect on the modulus is small. This is seen in the graph for a field whose 
strength is 0’7. In the next curve for field 2*6 the effect on the modulus 
is much more marked, and, both when the modulus is increasing and 
decreasing, the rate of change is greater than for the smaller field. The 
other curves are for increasing fields, and show the progressive change that 
takes place in the value of the modulus. There is a close correspondence 
between the results of the other method of experiment and this. In both 
we see that at first an increase of current is accompanied by an increase of 
the modulus, but that, when the current reaches a certain value, any further 
increase produces a diminution of the modulus. It is also to be noticed 
that there is a steady shift of the maximum value towards the zero of 
load, and that in the highest field, the value of which was 31 9, the decrease 
in the modulus was uniform. 
[Table. 
