ON THE RELATION OF THE HALL EFFECT TO TPIE 

 CURRENT DENSITY IN GOLD. 



By Thomas C. McKay. 



Presented by E. H. Hall, June 17, 1903. Received December 10, 1903. 



This subject was suggested to the writer by Professor Hall. The 

 work was carried on under his supervision in the Jefferson Physical 

 Laboratory of Harvard University. The subject was taken up as a 

 consequeuce of a paper of Moretto,* published about four years ago, in 

 which measurements of the Hall effect over a very large current range 

 were described, and results obtained at variance with the generally held 

 theory of the phenomenon. The results of previous investigators are 

 given first, with a general account of their work, in order that the subject 

 of inquiry may be clearly set forth. 



The first observations on this subject were made by Professor Hall,t 

 on the plate with which he discovered the general law of the phenomenon. 

 This was a strip of gold leaf, about 9 centimeters long and 2 centimeters 

 wide, mounted on a piece of plate glass. Contact was made with the 

 ends of the strip by pressing on them two pieces of polished brass. These 

 were connected to the terminals of a Bunsen cell. The terminals of a 

 high resistance Thomson galvanometer were connected to two opposite 

 points on the edges of the strip about midway between the pieces of 

 brass. The glass plate bearing the gold was cemented to the flat end 

 of one pole of the electromagnet and the other pole brought to within 

 6 millimeters of the strip. The following results were obtained: — 



* Moretto, Nuovo Cimento, Serie 4, 11, 278-289 (1900). 

 t American Journal of Mathematics, 2, 287-292 (1879). 

 iroL. XXXIX. — 23 



