HALL. — CONDUCTIVITY OF SOFT IRON. 127 



Temperature about 57° 0. 



Junctions. Deflections Along radii. 



13 and 13' 10.4 



1 and 1' 11. 



■■->) 



4 and 9.5 '>iQ7 2 ana z ll.D ^. 11.3 



7 and 7' 10.8 

 10 aud 10' 10.8 



9.6 



2 and 2' 11.5 \ 

 5 aud 5' 9.5 ( 



8 and 8' 10.G f 



11 and 11' 11.3 ^ 



8 and 8' 10.6 [ 



3 and 3' 11.0 ^ 9 aud <y 99 ) 



G and G' 9.7 



9 and 9' 9.9 



12 and 12' 10.6 > 1 and 11.3 ) 19.0 



>1 



I 



Mean, 10.5 

 All in multiple, 10.4 



It seems likely that the differences between the different radii are due 

 in part to inequalities of water-flow caused by the lodging of air-bubbles 

 at various points on or near the surfaces of the disk. 



The agreement between the deflection obtained with all junctions in 

 multiple and the mean of those obtained with the pairs used singly ap- 

 pears satisfactory, in view of the not very rigid character of the test by 

 which the comparison is made. 



The resistance of each individual pair of wires, out to the point where 

 all were connected in multiple, is shown in the following table, as it 

 was found July 12th, 1899 : — 



The deflections noted above are those of a rather sensitive astatic gal- 

 vanometer, the sensitiveness of which was frequently determined by 

 means of a potentiometer and a standard Carhart cell, or rather, two 



