304 



Mr. 



A. K. Chapman on the 





Field. 



Hall Effect. 



Corbino Effect. 





ind. H 



3700 



ind. H 



1650 



3930 



1750 



ind. H 



ind. H 



ind. H 



1700 



ind. H 

 3460 



-1-0 

 21-9 

 -0-73 

 - 19750- 

 - 12200- 

 421- 

 -0-46 

 -1-27 

 -1-60 

 -23-7 

 0-63 

 1-06 

 4-61 



-1-0 

 16-4 

 -0-48 

 -20100- 

 -16300- 

 557- 

 -0-56 

 -2-34 

 -1-61 

 -32-0 

 053 

 1-37 

 5-86 











Antimony 





Gold .., 



Silver 



Nickel 



Zinc 



Cadmium 



Cobalt 





The numbers given herewith under " Corbino Effect " are 

 values of m/H referred to copper and multiplied by the ratio 

 of the specific resistance of the particular metal to that of 

 copper. Multiplication by this factor brings the two 

 phenomena to the same order of magnitude, but the agree- 

 ment is not close except in one or two cases. Without 

 doubt this is due, in part, to the fact that the values were 

 determined for totally different specimens in the two 

 instances ; it will be shown later, however, that there 

 remains an outstanding difference between the two effects 

 when measured in the same specimen. Whether this dis- 

 crepancy is due to the free boundaries necessary in the Hall 

 effect, to some difference ininternal behaviour, orto both, seems, 

 in the present state of onr knowledge, impossible to say. 



Assuming that, in the Corbino effect, the function of the 

 magnetic field is to produce an electromotive force at right 

 angles both to the magnetic force and to the primary current, 

 and that this electromotive force is proportional to the vector 

 product of H, the magnetic force, and E, the primary 

 electromotive force, we have 



E^cVHE, 

 where V indicates the vector product, E x is the electro- 

 motive force of the Corbino effect, and c is the proportionality 

 factor (E. P. Adams, Proc. Am. Phil. Soc. vol. liv. no. 216, 

 1915). Applying this to a disk of the form used in these 

 experiments, we have 



C=^log-MH, 



2lT w T Y 



w r here C is the total circular current, I 

 current, r 2 is the external radius of the 

 internal radius of the disk. We may then call 



2ttC 



is the total 

 disk, and r Y 



radial 

 is the 





the Corbino constant. 



HI log 



