646 



On the Hysteresis of Nickel and Cobalt. 



centimetre per cycle. As the intensity is increased from this 

 point to the highest value attained — viz , 475 C.G.S. units 

 produced by an applied field of 460 C.G S. units — the hys- 

 teresis loss rapidly falls off. The latter portion of the curve 

 is sensibly a straight line, and if it were to retain this 

 character over the unexplored region, the hysteresis would 

 disappear entirely at an intensity of 500 C.G.S. units, which 

 is about equal to the saturation-intensity of nickel. 



Table I. 



—Nickel. 



Intensity of Magnetization 



Hysteresis Loss in Ergs 



in C.G.S. units-. 



per cub. centim. per Cycle. 



46. 



675 



125 



3,120 



165 



5,060 



200 



6,940 



264 



9,300 



296 



9,710 



342 



9,920 



370 



9,440 



412 



8,300 



436 



7,220 



460 



4,550 



475 



2,700 



Table II. 



—Cobalt. 



Intensity of Magnetization 



Hysteresis Loss in Ergs 



in C.Gr.S. units. 



per cub. centim. per Cycle. 



80 



2,780 



160 



6,950 



2f0> 



11,100 



340 



18,100 



430 



22,200 



526: 



28,500 



650- 



35,400 



725 



35,400' 



800» 



34,000 



865 



29,900 



910 



24,300 



945 



17,400 



970 



13,900 



980' 



11,800 



In Table II. and the "Cobalt" curve of fig. 2 are shown 

 the results of experiments on a disk of rolled cobalt '0815 cm. 

 thick and 3*96 cms. in diameter. The maximum hysteresis 

 loss for this material (36 ; 000 ergs per cubic centimetre per 

 cycle) occurs at an intensity of 700 C.G.S. units, and is very 



