240 TRANSVERSE EFFECT AND ON SOME RELATED ACTIONS IN BISMUTH. 



cannot, therefore, be due to this heating effect, otherwise its direction would be independent 

 of that of the primary current. We must rather suppose that it is the result of a kind 

 of Peltier effect, arising from the heating of a substance differently deformed in different 

 parts. Should this be so, it might be possible to map out a plate into pressed and 

 stretched regions by observing the direction of the effect in different parts of the plate. 



For let us assume, after Bidwell,* that the plate is deforming in the following manner 

 so that A B represents a compressed part, B F a stretched, and so on ; then if the electrodes 

 are at L and M, the current is in the direction L M ; should they be at N and the 

 current would be in the direction N 0, — that is opposite to the former (fig. F). 



If such be the explanation, we should expect to find an electromotive force created in 

 a heated body when it is placed in a magnetic field ; this has been observed by Ettings- 

 hausen and Nernst.1' 



* Phil. Mag., 1884. 



t Wiedemann's Annalen, 1887, Bd. 31. 





