30 W. G. Levison—Electrotytic Phenomena. 
amalgam is observed, which seems to arise from its being 
raised in the center while the current flows and its falling to 
the normal level when it is interrupted. 
ile the circuit is broken there is a constant evolution of 
hydrogen gas in very fine bubbles from the entire surface of 
the amalgam. When the circuit is closed they no longer 
escape freely at the point of evolution, but glide over its sur- 
face from all sides toward the center where they coalesce to 
form large bubbles, which there escape. These bubbles are 
abnormally spread or flattened out upon the surface of the 
amalgam, escape with a peculiar trembling as if with difficulty, 
and if caught under the porous cup they still exhibit the flat- 
tened aspect. On breaking the current they become hemis- 
pherical and again escape readily from all parts of the liquid 
surface. Some of the phenomena thus observed I have since 
the end as if it tended to part at that point and the negative 
