RESEARCHES OX MAGNETOSTRICTION. 



367 



coil. The lower end of the ovoid was placed in a conical hole, bored 

 in the end screw K fitting: into the main tube T. To prevent disloca- 

 tion of the ovoid and to keep it always vertical, the upper end was 

 loosely fitted into a triangular hole in the brass plate A in the manner 

 already described in the determination of the change of volume. The 

 neck of the vessel consisted of a smaller brass tube provided 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. 



The vessel was connected with the copper tube from the pump by 

 a screw nut N. Before an experiment, it was .always necessary to 



apply the pres- 

 sure of more than 

 250 atmospheres 

 to test if there 

 was no leakage at 

 the screw joints. 



T w o su c h 

 brass tubes, T and 

 T", each contain- 

 ing a magnet of 

 the same geome- 

 trical form and 

 size, were placed 

 in the solenoids, 

 S and IS' (Fig. 3), 

 which also were 

 - 1 of equal dimen- 

 sions, as shown in 



Fig. 3. 



JLJL 



S' 



M 



