360 



Dr. J. R. Ashworth on the Anliysteretic 



diminished the magnetic intensity retraces its path up to 

 2 a = 0"5, but for lower values of i a it continues to increase, and 

 does not come back to the original low value. This is 

 specially observable for low field strengths. There is, there- 

 fore, a critical strength of alternating current. 



That the smooth parts of these curves are very nearly 

 rectangular hyperbolas is shown from the fact that the 

 reciprocals of I when plotted against i a fall very nearly on 

 straight lines, the only serious irregularity being for the 

 curve of H = 0'55, in which the observations would be 

 affected by a larger error than for higher fields. These 

 straight lines when prolonged backwards all meet approxi- 

 mately at a common point which is situated about O00085 



on the scale of j, and at nearly —1*1 on the scale of 



i a . It is possible to express these curves above the critical 



