042 



Messrs. K. Honda and S. Shimizu on 



values given by Noll (loc. cit.) and by Maclean* for tl un- 

 drawn " and " drawn " wires have been made use of. 

 Maclean's "annealed steel" is taken as the equivalent of iron. 



Excess of " Hard " over " Soft." 





Noll. 



Maclean. 



Scbmitz. 



Copper-Iron 



-j-2 per cent. 

 +2 per cent. 

 +2 per cent. 



— 1 per cent. 

 +3 per cent, 

 -f ^ per cent. 



— A\ per cent. 

 + 5| per cent. 

 + | per cent. 



G-.S. -Copper 



G.S.-Iron 





LXXI1. On the Magnetization and the Magnetic Change of 

 Length in Ferromagnetic Metals and Alloys at Temperatures 

 \ ranging from -186° C. to +1200° C. By K. Honda, 

 Pigakuhakushi, Lecturer in Physics, Tokyo University, and 

 S. Shimizu, Rigakushi, Lecturer in Physics, High Normal 

 School. 



[Concluded from p. 574.] 



III. Third Series. 



IN the third series of experiments the magnetization was 

 measured at different stages of ascending as well as 

 descending temperatures, the measurement of the change of 

 length by magnetization being left for future experiments. 



The heating was effected by means of an electric current ; 

 a porcelain tube (external diam. = l*7 cm., internal diam. 

 = 1'05 cm., length = 47 cm.) was covered with a few layers 

 of asbestos paper, and the lower part (36 cm.) was wound 

 anti-inductively with a platinum wire 0*4 mm. thick at the 

 rate of 2 turns per cm. It was then wrapped in asbestos 

 papers to a thickness of about 5 mm. To the upper end of 

 the porcelain tube a brass flange was fixed, while a short 

 porcelain cylinder was inserted tightly in its lower end so as 

 to arrest air currents. The length of this cylinder was so 

 chosen that when the tube was placed in the right position in 

 the central line of the magnetizing-coil the ovoid occupied 

 the central position of the coil. The magnetizing-coil was 

 provided with a water-jacketed arrangement and a coil for 

 the compensation of the vertical component of the earth's field. 



The temperature of the ovoid was measured with a platinum 

 rhodium-platinum junction. One of the junctions was placed 

 in contact with the specimen at a point a quarter of the 



* Proc. Roy. Soc. vol. lxiv. p. 322 (1899), and vol. lxvi. p. 165 (1900). 



