A. S. Kimball—Magnetic Strains in Iron. 105 
be less than those obtained by decreasing the load. The 
changes in deflection the first time the current is broken will 
be less than those which follow. 
Ilustration—8 Ibs. have just been removed while the cur- 
rent was passing. 
ee G. H. 1 thee G. H. 4 
Mo we SS eS er ae LS a 
a BT OR se 202. BOL eae ae 
RES Re ee, Page eee BF ic wiuge gig Mie ieee ee 
9th. Changes in deflection produced both by the first and 
by subsequent currents increase with the load on the bar up 
to the elastic limit, when they tend to become constant. 
Below the elastic limit, the law may be approximately expressed 
by the following formula : 
(change)?=a (load+-8). 
r, we find, at the outset, that, though some of them are 
explained readily, others appear contradictory, and others still » 
need additional data. A series of experiments was next 
obtained by those accurate experimenters have been repro 
T. * 
[Since making the a8 STE described in this paper, the 
writer has noticed a reference to an article by M. Guillemin, on 
t 
