119 
on the resistance of thin metallic films. 
The following table gives the results obtained : 
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 -5 
58*04 
1-38 
26200 
•16 
•27 
146 
27500 
•18 
•31 
154 
1 
1-3 
6 x 10~ 6 
103 05 
1-44 
26200 
•055 
•053 
146 
27500 
•061 
•059 
154 
1*2 
1*3 
4 x 10 -6 
968-7 
3-46 
26200 
•! 
•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 682 2 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. 
