159 



A Modified Permeameter. 



Edwin Morrison and B. D. Morris. 



Ill his work on the Magnetic Induction in Iron and Other Metals, Ewing 

 briefly describes a permeameter. (See page 247, Art. 148.) The instrument 

 is for the purpose of determining the magnetisation of a metal bj^ means of 

 tlie tractive force. In Swing's work the permeameter method constitutes 

 the fourth method of measuring the magnetic properties of a metal, that of 

 the ballistic, the direct magnetometric, and the optical methods having been 



"Utr,, thai 



L=U, 



^ 



r,^. m. 





fTj ( 



previously described. After describing the apparatus and developing the 

 equations the author closes his discussion thus: "The tractive method is at 

 best inexact, but it affords a ready means of making rough measurements, 

 especially for purposes of comparison." 



