Tables 290-296. 

 MAGNETIC PROPERTIES OF METALS. 

 TABLE 290. - Cobalt at 100 C. TABLE 291. —Nickel at 100' 0. 



TABLE 292. — Magnetite. 

 The following results are given by Du Bois * for a specimen of magnetite. 



Professor Ewing has investigated the effects of very intense fields on the induction in iron and other raetals.t The 

 results show that the intensity of magnetization does not increase much in iron after the field has reached an in- 

 tensity of 1000 c. g. s. units, the increase of induction above this being almost the same as if the iron were not 

 there, that is to say, dBj dH is practically unity. For hard steels, and particularly manganese steels, much higher 

 forces are required to produce saturation. Iladfield's manganese steel seems to have nearly constant susceptibility 

 up to a magnetizing force of lo.ooo. The following tables, taken from Ewing's papers, illustrate the effects of 

 strong fields on iron and steel. The results for nickel and cobalt do not differ greatly from those given above. 



TABLE 293. — Lowmoor 

 Wrought Iron. 



TABLE 294. — Vicker's 

 Tool Steel. 



TABLE 295. - Hadlleld's 

 Manganese Steel. 



TABLE 296. —Saturation Values for Steels of Different Kinds. 



Bessemer steel containing about 0.4 per cent carbon . . . 

 Siemens-Marten steel containing about 0.5 per cent carbon 

 Crucible steel for making chisels, containing about 0.6 per 



cent carbon 



Finer quality of 3 containing about 0.8 per cent carbon . . 

 Crucible steel containing i per cent carbon 



H 



17600 

 18000 



19470 



18330 

 19620 



Whitworth's fluid-coinpressed steel | 18700 



1770 

 1660 



1480 

 1580 

 1440 

 1590 



39880 

 38860 



38010 

 38190 

 37690 

 38710 



2.27 

 2.16 



1-95 

 2.08 



1.92 



2.07 



* " Pliil. Mag." 5 series, vol. xxix. 



t " Phil. Trans. Roy. Soc." iSSs and 1S89. 



279 



