216 A. Tanakadate on the Thermal Effect due 



Horizontal intensity of the earth's field . *152 C.Gr.S. 

 Ballistic throw caused by one complete 



revolution of the coil about a vertical axis 



fixed in the plane of the coil .... 15 scale-divns. 

 This was mean of five observations agreeing amongst them- 

 selves within J division. 



Number of turns of the secondary coil 



over the rings 100 



Total area of the sections of iron wire 



in the ring, 130 x -t(*115) 2 . . . . = 1*35 sq. centim. 



Resistance of the secondary coils . . . '605 ohm. 

 Resistance of the galvanometer . . . '634 ohm. 

 Resistance of the leading wire .... *229 ohm. 



Whence the total resistance in the circuit 

 when the change of magnetization was 

 experimented upon ...... 1*468 ohm. 



From those numbers the value of 3, the intensity of magne- 

 tization corresponding to one division of the ballistic throw is 

 167640x2x*152 1-468 ,„ n . n n a 

 15x1*35x100x477 5*169 

 Figs. 24, 25, 26 show the curves of magnetization when 

 the magnetizing field «£) was cyclically varied between given 

 limits. Each curve consists of two consecutive cycles ; the 

 points belonging to the first cycle are marked by dots, and 

 those belonging to the second by crosses. The areas of those 

 cycles j 3^«& were calculated by Simpson's method, and gave 



severally f 3 ' 8 c\7<x iaka t 



I 3d«& = 1050 ergs I. 



•/ -3-8 



3-2£ = 6690 „ II. 



J -8' 



f 



3d£ = 13610 „ III. 



-21 



The ring was now undone and 33*4 centim. of the iron wire 

 was cut off, straightened and annealed, and then the curve of 

 magnetization was studied by the magnetometric method. The 

 result was anticipated in Phil. Mag. Nov. 1888, p. 450, in 

 connexion with another research, where 



1 



51 



3t?£ = 18450 ergs IV. 



■51 



Now if the whole work so done upon the substance of iron 

 oy cyclic change of magnetization be assumed to be used up 



