8 



ART. 6, — K. HONDA AXD S. SHTMTZU. 



ANNEALED COBALT. 



From these numbers, we see that in Swedish iron, tungsten 

 steel and nickel, the cooling- by liquid air diminishes the mag- 

 netization in low fields, but increases it in the strong. In Swedish 

 iron and tungsten steel, the cliange is very small, amounting at 

 most to 2 or 3 per cent ; but in nickel, the initial diminution is 

 considerably larger, amounting to about 10 per cent in the 

 maximum. The field, in which the effect of cooling changes its 

 sign, is 115 C.G.S. for Swedish iron and tungsten steel, and 

 580 C.G.S. for nickel. Fleming aud Dewar'^' who first thorough- 

 ly studied the magnetization of iron and steel in liquid air, did 

 not observe an increase of magnetization ; perhaps the field was 

 too weak to indicate such an increase. 



In cast and annealed cobalts, cooling always diminishes 

 magnetization ; the effect is rather greater in cobalt when annealed 

 than in the cast state. 



*) Fleming and Dewar, Pm, Roy. Soc, 60, 81, 1896. 



