154 
IOWA ACADEMY OF SCIENCE Voi,. XXIX, 1922 
orated iron its value is from 600 to 1000 per cent greater than 
that for pure bulk iron. 
These phenomena are interpreted as a consequence of the small 
granules in evaporated metals, in the following way: 
1. The effect of granular boundaries is to increase the resis- 
tance of a specimen. 
2. The current contributing to Hall effect is decreased upon 
increasing the number of gaps in any cross section. 
3. The Hall effect depends upon the magnetic condition of a 
substance, which in turn depends upon the granular dimensions. 
Department oe Physics. 
State University oe Iowa. 
