38 ART. 6. K. HONDA AND S. SHIMIZU. 



From these numbers, we find a parallelism between the change 

 of magnetization and that of the length-change. In weak fields, 

 the change of length gradually increases as the temperature falls, 

 till it reaches a maximum, and then decreases. As the field 

 becomes stronger, the maximum elongation is displaced in lower 

 temperatures, and at last vanishes. These changes are common 

 to nickel steels of percentages higher than 28.32^0 ; for percent- 

 ages lower than 26.64 ?o, the elongation for a constant field at 

 first increases gradually and then rapidly, soon approaching an 

 asymptotic value, as the temperature falls. 



III. THIRD EXPERIMENT. 



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 mag- 

 netization being left for future experiments. 



The heating w^as effected by means of an electric current ; 

 a porcelain tube (external diam. = 1.7 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 to its lower end, a short porcelain cylinder 

 was inserted tightly, so as to arrest air currents. The length of 

 this cylinder was so chosen tliat 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 mag- 



