46 Art. 6. — k. honda and s. shimizu. 



drawn in Fig 6 c, in which the results of the first experiment 

 were also included. The character of the change of magnetization 

 by heating coincides with the results obtained by the former in- 

 vestigators*. Here the range of the temperature is considerably 

 extended on the negative side of zero temperature. It is remarkable 

 that though the magnetization falls very rapidly near the critical 

 temperature 360°C, its further decrease is very small, and even at 

 1200°C, a magnetization of about 6 C.G.S. for H=400, is still ob- 

 served. This important phenomenon was first observed by Curie. 



(6) iVIagnetization of Nickel Steels. 



In nickel steels, the magnetic state after cooling in liquid 

 air slightly changes as the time proceeds. In some alloys, it 

 does not return to its initial state, when they undergo a cyclic 

 change of temperatures between — 186°C and 1100°C. This change 

 of character is greater in the irreversible alloys than in the 

 reversible. 



The magnetization of the alloys at different temperatures 

 presents a striking contrast between the reversible and the irre- 

 versible alloys. Some of the interesting results had already been 

 obtained by previous investigatorsf. 



The manner in which the magnetization of the reversible 

 nickel steels changes with the temperature is similar to that of 

 nickel, as given in Table XI. 



"■■) J. HoPKiNsoN, loc. cit. Curie, loc. cit. Nagaoka and Kusakabe, loc. cit. 



t) H. Eecqueeel, C.R. XCIII, p. 794, 1881 ; J. Hopkinson, Pro. Roy. Soc, XLVII, 

 p. 23, 1890, and XLVIII, p. 1, 1890 ; H. Le Chateijer, C.R., CX, p. 283, 1890 and CXI, 

 p. 454, 1890; H. Tomlinson, Pro. Roy. Soc, LVI, p. 103, 1894; F. Osmo>-d, C.R, CXVIII, 

 p. 532, 1894, and CXXVIII, p. 304, 1396, 1899; Ch. Ed. Guillaume, CR., CXXIV, p. 

 176, 1515, 1897; CXXV, p. 235, 1897; CXXYI, p. 738, 1898; Les aciers au nickel, Paris 

 1898; E. DuMONT, C.R., CXXVI, p. 741, 1898; L, Dumas, C.R., CXXX, p. 357, 1900. 



