UPON MAGNETISATION, AND CONVERSELY, IN IRON, STEEL, AND NICKEL. 505 



nickel than in quenched iron and steel. In this respect quenched nickel more nearly 

 resembles the annealed metals. 



The observations from which these curves were plotted show that B v — B, as in 

 the annealed metals, does not reach a maximum until H is further increased. In 

 nickel, B v — B is a little greater than in either iron or steel (1000 as against 700). 

 In the annealed metals the opposite was the case. 



QUENCHED 



B. CONDITIONS. 



6 12 



FIG XIII STEEL 



18 



2 



FIG XII IRON 



B 



,/b b v -Rv/b-r. 



Residual Magnetisation in Relation to Field. — Permanently acting vibrations 

 increase] ^or decrease residual magnetisation as the fields are low or high ; but the 

 former effect is very much less in quenched iron and steel than in quenched nickel. 

 This accounts for the fact that in quenched iron and steel the retentivity curves with 

 vibrations (Ry) never rise above the normal induction curves without vibrations (B), as 

 they do in the annealed metals and in quenched nickel. 



