McKAY. — HALL EFFECT AND CURKENT DENSITY IN GOLD. 357 



magnetic field, again with the magnetic field in a given direction, then 

 with the magnetic field in the opposite direction, and lastly without a 

 field. A numerous series of determinations was made which gave 

 results of the kind indicated by the following table, the only table of 

 results bearing on our question in Moretto's paper. 



Strength of Field — 9600 C. G. S. Units. 



q y and q* are the quantities in cubic centimeters of a ^^o^ n normal 

 solution of sodium hydrate, formed by the passage of the two partial 

 currents respectively ; / is the main current, and equal to the sum of 

 the two partial currents ; w is obtained by taking the difference made 

 in each partial current by reversing the field, summing these differences, 

 and dividing by 2. Moretto does not state the metal used in obtaining 

 this series of results. It was probably bismuth. 



The measurement of w depended on a small difference of the partial 

 currents, which were not measurable with the highest accuracy. An 



