Electric Current on the Thinning of a Liquid Film. 99 
became blurred and indistinct, and in two minutes the black 
had disappeared, white taking its place. The current rose to 
5:32m.a. The circuit was then broken. Three millim. of black 
having been formed in seven minutes, the current was again 
put on (C=4°2 m.a.). The fuzziness at the edge reappeared 
at once, and in two minutes the black was all gone. The 
current rose to 4°62 m.a. 
(3) Film 19 millim. long, entirely black from top to bottom. 
Upward current of 3°12 m.a. put on. In thirty-eight minutes 
the current rose to 4°23m.a.,and the film was white throughout. 
(4) Film 30 millim. long. Black appeared in ten minutes. 
When it had increased to 5 millim. the circuit was completed. 
C = 5:05 m.a. In one minute all the black had disap- 
peared, and in two minutes more the film had a uniform tint 
throughout, while the current rose to 14°5 m.a. 
(5) Film 30 millim. long. Upward current passed through 
. from the beginning. It was not measured at first, but after 
five minutes its strength was 20 m.a. This increased to 28:5 
m.a., which was maintained for several minutes, after which 
it slowly fell. The film was colourless. 
The ring of liquid on the upper platinum support was seen 
to increase in thickness and to become wavy along its lower 
edge. Pendent drops were formed, pointed at the bottom, 
and hanging from the liquid fringe. 
From the points of the drops tiny 
streamlets were seen flowing down the 
film. This is a very remarkable experi- 
ment. The up-current not only retards 
the thinning, but actually increases 
the thickness of the film. The strength 
of the current was not observed at 
first; but from the moment when it 
was observed until it reached its maxi- 
mum it increased by over 40 per cent., 
and the thickness of the film must 
have increased in nearly the same proportion. In opposition 
to gravity the current carries liquid to the top of the film, 
where it accumulates and from which it descends in liquid 
veins. 
The phenomena mentioned above recurred in several other 
films similarly treated. In some cases the film lasted long 
enough after the circuit was broken for black to be formed 
and to-extend to a considerable depth; and the curious 
spectacle was exhibited of pendent drops of thick colourless 
liquid penetrating through the black to a distance varying 
from 4 millim. to 93 millim. 
