MAGNETIZATION A N I » MAGNETOSTRICTION. 9 



increases. Ultimately, with further additions of nickel, the maximum 

 elongation makes its appearance, and is already ptesenl for .">(). 72 per 

 »■nit in field of LOOO Gauss ; with 70.32 per cenl Ni., this occurs in 

 £?=J70. It thus appears that the increase of nickel beyond 50 per 

 cenl displaces the maximum point in the direction of the 

 lower field. In fact, the character of the change resembles that in 

 iron. With further additions of nickel, the metal will show contrac- 

 tion, which goes on increasing with the field. This remarkable change 

 in the character of elongation will probably occur, when the metal 

 approaches pure nickel. Further it is to be noticed that the elonga- 

 tion in all these specimens exceeds that of the constituent 

 ferromagnetics. 



An examination of fia*. 4 discloses how the transition between 

 the elongation in iron and the contraction in nickel takes place. The 

 curves of elongation plotted against the percentage content of nickel 

 are similar to those of magnetization, showing two maxima and two 

 minima between 24 per cent and 50 per cent of nickel. The alloy 

 indicating the maximum elongation is little greater than 40 per cent, 

 which nearly coincides with that showing greatest susceptibility. 



