TRANSVERSE EFFECT AND ON SOME RELATED ACTIONS IN BISMUTH. 239 

 The same plate planed to thickness, 0'08277 cm. 



Field, 





15-7 . 



28-2 



66-7 



94-2 



110-0 



147-0 



Effect, 





0-0068 



0-02114 



0-0608 



0-0878 



01045 



0-122 





Plate III. 







Length, .... 



1-99 cm. 





Breadth, .... 



1-075 





Thickness, .... 



0-12697 „ 



Field, 





98-0 



138-0 



146-0 



153 



Effect, 





0-0362 



006246 



0-06349 



006904 



The 



same plate was planed to thickness, 0*09 cm. 





Field, 



. 



33-8 



61-0 



93-2 





110-0 



1530 



Effect, 



• 



0-0125 



0-03061 



0-04977 



00609 



0-06831 



It will be observed that in Plate I. a maximum effect is reached just as was the case 

 with the transverse effect in that plate ; and in II. and III. no such maximum effect 

 was reached again agreeing with the transverse current. 



The same effect was observed and measured in Plates VIII. and IX. ; in those plates 

 which gave a reversal of the transverse current ; the result was too small tb be measured 

 accurately. In some cases, however, it was noticeable and always directed against the 

 transverse current. In those plates in which the effect was observed, it must be added 

 to the transverse effect to give the latter its proper value. 



To find how this effect depended on the current, the field was kept constant, and four 

 different currents used. 



Primary Current in Scale Parts. 



Effect in Scale Parts. 

 Primary in Scale Parts. 



60-0 

 124-1 

 187-1 

 3730 



0-06458 

 0-06305 

 0062 

 0-06246 



or for the currents used, the effect is proportional to the current. 



To explain this effect we must remember that the body carrying the current in a 

 magnetic field is subject to mechanical force and is also heated by the current. Accord- 

 ing to Joule's law the heating is proportional to the square of the current strength ; it 



