362 



H. NAGA0KA AND K. HONDA 



of the liquid due to the heating of the coil. We consider that the 

 present mode of filling a dilatometer provided with fine capillary 

 tube can be successfully applied in other cases of a similar nature. 



The ovoid was placed in the middle of the magnetizing coil 

 and the rise or fall of the meniscus in the capillary tube was 

 observed by means of a microscope with micrometer ocular. Al- 

 though the resistance of the coil was only 0.6 ohm, the heating 

 effect was considerable, so that only an instantaneous observation could 

 be made. This difficulty was to a great extent overcome by pass- 

 ing the current for some time in the coil : the ovoid was then 

 demagnetized by the method of reversals ; waiting for a time, the 

 meniscus became stationary, the magnetizing current was then made 

 and the reading taken. The measurement was made in a dark room, 

 witli eras-light vvith ground glass shade at some distance behind the 

 capillary tube ; by this arrangement, the meniscus was sharply defined. 



The following table gives the determination of the change of 

 volume in the iron ovoid and cylinder by magnetization. 



Ovoid. 



Cylinder. 



