Messrs. H. Nagaoka and K. Honda on Magnetostriction. 271 



with a flange F; by means of a strong brass screw S attached 

 to F the whole vessel can be slowly moved in the solenoid, 

 so that there was no difficulty in placing the magnetized body 

 in proper position for experiment. 



Kar. 2. 



The vessel was connected with the copper tube from the 

 pump by a screw-nut N. Before experiment it was always 

 necessary to apply a pressure of more than 250 atmospheres 

 to find if there was leakage at the screw-joints. 



Two such brass tubes T and T', both containing the magnet 

 in the same geometrical form, were placed in the solenoids 

 S and S f (fig. 3), which also were of the same dimensions, as 

 shown in the accompanying figure. The coils were each 40 

 cm. long, wound in six layers, and gave the field of 17*7 

 C.G.S. units for a current of one ampere. The magneto- 

 meter M was placed midway between the solenoids, due 



