4 ART. 6. — K. HONDA AND S. SHIMIZU. 



were to be studied with the ovoids placed in vertical positions. 

 Though these precautions were taken with the utmost care, the 

 magnetizations by opposite currents of equal strength were not 

 exactly equal in absolute amounts, so that a small asymmetry of 

 the hysteresis curve was also observed in the strong fields. This 

 difference was, in the most unfavorable case, not greater than l"/o of 

 the total magnetization for a field of 700 C.G.S. This probably 

 arose from a slight deviation of the coils from the vertical line. 

 If the lines of force at the center of the magnetometer be not 

 vertical, but be in the meridian plane, the field due to the coils 

 may slightly affect the horizontal component of the earth's field, 

 without producing any deflection of the magnetometer. If the 

 horizontal component be increased by a current in one direction, 

 a current in the opposite direction will diminish it. In the first 

 experiment, therefore, two magnetizing curves for opposite currents 

 were taken. These two curves almost coincided wdth each other 

 below a field of 200 C.G.S. , but slightly deviated above that field. 

 Since the disturbing force is proportional to the magnetizing 

 current, the correction for the intensity of magnetization can 

 be derived from a pair of the opposite magnetizations by equal 

 and opposite currents ; hence in the second and third experiments, 

 the magnetizations by equal and opposite currents of the maxim- 

 um strength were taken, and the correction was found, and 

 applied to magnetization by currents of one direction. 



The current was measured by a Si em en-Hals kï: ammeter, 

 which was occasionally compared with a Kelvin ampere-balance. 



The experiment was conducted in the following order. The 

 adjustment of the magnetizing and compensating coils having been 

 completed, the specimen-holder containing the ovoid was fixed ver- 

 tically in the correct position in the magnetizing coil. The ovoid 



