NOTE ON THE IRON-TURNINGS CELL. 
7 
the capillary pressure on the gas will be diminished ; so that an 
increase in thickness corresponds to an increased rate of flow 
from a projection to a neighbouring hollow, and hence it follows 
that if the current in the cell is increased so as to increase the 
rate of evolution of hydrogen at A, the polarizing layer must 
increase in thickness to effect a corresponding increase in the 
rate of delivery at B, and if the polarizing efficiency of the 
gaseous film increases with its thickness we have here the 
explanation of the observed diminution of electromotive force 
with an increased current. 
