92 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



TABLE III. 



Ring of the Pure Annealed Norway Iron. {Rectangular Cross Section. 

 Inner Radius, 2a; Outer Radius, 3a.) 



^0 ^rid Bq are the values of the magnetic force and of the induction at 

 the inner surface of the ring; H\, Bi and Hm, Bm the values of the same quan- 

 tities at the outer surface of the ring and at the mean radius, respectively. 

 H' is the mean value of the magnetic field in the steel. B' is the mean value 

 of the induction in the ring as obtained by mechanical integration from a 

 diagram of ascending reversals for the steel, and B" is the value of the induc- 

 tion corresponding to H' as shown by the same diagram. The table shows 

 the error made by using, B' /H' instead of the exact value B" /H' for the 

 permeability corresponding to H'. 



TABLE IV. 



Thinner Ring of the Annealed Noi'way Iron. {Rectangular Cross 

 Section. Liner Radius, ia; Outer Radius, 5 a.) 



