258 PROCEEDINGS OF THE AMERICAN ACADEMY. 



fourth or fifth hysteresis cycle following, assuming that that is the num- 

 ber introduced between the two 1-step processes. If in continuing the 

 work two steps be introduced in place of the one and they are in turn 

 always the same, the same conclusion can be drawn in regard to their 

 influence. If finally the flux changes produced by the 1-step and 

 2-step processes were identically equal, it is evident that, when the 

 iron is retracing each time the same hysteresis curve, it makes no differ- 

 ence whether that part of the curve tested be passed over in two steps 

 or one. 



For a maximum flux of 13,000 the following data was obtained in the 

 manner just described. 



The iron was demagnetized. 



Test of Ballistic Galvanometer. 



Amperemeter Heading. Ballistic Throw. 



13.75 21.30 



13.77 21.35 



The iron was carried through 14.5 hysteresis cycles of forty-four steps 

 each and back on the last half of the 15th until H was about 1.2. 

 The field was then. reduced to zero and the flux change observed on 

 raising it to its full value in one step. 



Amperemeter Reading. Balliatic Throw, 



1.220 21.89 



The iron was carried through 4.5 cycles ; the next half cycle was 

 treated as above : 



Amperemeter Reading. Ballistic Throw. 



1.222 21.98 



The iron was carried through 4.5 cycles ; the next half cycle was 

 treated as above : 



Amperemeter Reading. Ballistic Throw. 



1.223 21.92 



The iron was carried through 4.5 cycles ; the next half cycle was 

 treated as above : 



Amperemeter Reading. Ballistic Throw. 



1.224 21.96 



The iron was carried through 4.5 cycles ; the next half cycle was 

 treated as above except that two steps replaced the one : 



