16 



ART. 6. — K. HONDA AND S. SHIMIZU. 



in liquid air, tlie intensity of magnetization increases from 16 to 

 1275 for H = 600 C.G.S., or by about 80 times. 



The magnetizations, before and after cooling, of reversible 

 nickel steels containing greater percentages of nickel than 36^, 

 nearly coincide with each other. If, however, irreversible nickel 

 steels be once cooled in liquid air, the recovery to the initial 

 value becomes less and less, as the percentage diminishes ; in 

 24.40^^ and 24.04^ nickel steels, the magnetization after cooling 

 is even greater than that in liquid air. Some of the above results 

 had already been obtained by Hopkinson'^ OsMONDf, and DumasJ. 



(c) Hysteresis-loss in Ferromagnetic Substances. 



The hysteresis was studied at the temperature of the room 

 and at that of liquid air. The areas of the hysteresis-loops were 

 carefully measured by a planimeter with the results given in 

 Table III. and in Fig. 1 a, b. 



TABLE III. 



FERROMAGNETIC METALS. 



*) Hopkinson's original paper.s, Vol. II, p. 227. 



t) Osmond, C.R. CXXVIIl, p. 30G and i:!96, 1899; CR. CXVIII, p. 532, 1894. 



t) Dumas' Recherches sur les Aciers tni Nickel, p. 49 — 67, 1902. 



