242 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



o 



REVERSALS 



100 



X 



200 



Figure 4. Set II: B 6000: first magnetization; all 1-step reversals except 

 the 196th and the 198th, which are 3-step. 



Again there is a very slight fall in the maximum B as the number of 

 reversals increases. The 3-step and 1-step processes yield the same 

 results to within 5 parts in 2250. 



From these three sets of data it is evident that the effect of the 

 method of magnetization is, in so far as the number of steps is con- 

 cerned and these tests are carried, of no consequence. In the worst 

 case the difference between the total flux change for 1-step and 3-step 

 reversals is one third of one per cent, and in the best one tenth of one 

 per cent. 



It is important to note that such a statement applies only when 

 the iron has reached such a state that it passes repeatedly through 



