on the resistance of thin metallic films. 

 The following table gives the results obtained : 



119 



Dimensions of film in cm. 

 Length Breadth Thickness 



Resistance 

 in ohms 



Resistance 



calculated 



from 



specific 



resistance 



Magnetic 

 field in lines 

 per sq. cm. 



Increase 



of 

 resistance 



% increase 



»/o in- 



crease of 



bismuth 



wire 



1-4 



1-3 



1 x 10- 3 



58-04 



1-38 



26200 

 27500 



•16 

 •18 



•27 

 •31 



146 

 154 



1 



1-3 



6 x lO- 6 



103-05 



1-44 



26200 

 27500 



•055 

 •061 



•053 

 •059 



146 

 154 



1-2 



1-3 



4 x lO" 6 



968-7 



3-46 



26200 



•1 



•01 



146 



These results shew that the change of resistance in the magnetic 

 field is not only very much smaller than that of bismuth in form 

 of wire but that the change of resistance decreases with the 

 decrease in the thickness of the film. 



A film of cobalt 1*4 x 1*3 cm. with a resistance of 6822 ohms 

 was made, but in a field of 27500 lines no change could be 

 detected. 



In concluding this preliminary note, the author desires to 

 thank Mr C. F. Mott for kindly placing his apparatus for making 

 the films at the author's disposal, and to Prof. J. J. Thomson for 

 his interest and suggestions. 



