48 ADAMS— HALL AND CORBINO EFFECTS. [April 22, 



assume that the effect of the magnetic field is to produce an electric 

 intensity at right angles to both the magnetic force and to the pri- 

 mary electric intensity, and proportional to their product and the 

 sine of the angle between them. This we may take to be: 



E'=cVHE, 



where V stands for the vector product. Applying this to the Cor- 

 bino effect in a circular disk where r, is the external radius and r-^ 

 the internal radius we find: 



I 



E = 



2Ttktr ' 



where / is the whole radial current, k, the specific conductivity, 

 and t the thickness. Then the transverse electric intensity is 



C To 



C = — log - . IH. 



27r fi 



Therefore the constant a is equal to (c/27r) log (^a/rj 



C 27r 



c = 



IH ^ r.' 



log- 



We may now make the same hypothesis about the Hall effect. 

 Here it is known that if a current / flows through a rectangular 

 sheet metal of length /, breadth b^ and thickness t, there is a trans- 

 verse difference of potential given by 



HI 



R being the Hall constant. The transverse electric intensity is now 



E' = '-^^ 



kU • 



