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two extremities of the metallk arc soon acquired, by 
the law of induction, electricities the opposite to 
those possessed by the Galvanic wires. Consequent- 
ly, the effects of a double battery were obtained, 
and, in each glass, two particle of water were de- 
composed, just as happens in one glass, when the 
two wires of the battery approach each other. 
448. This fact was rendered very obvious by an 
ingenious and simple variation in the mode of making 
the experiment. The wires of the battery were 
made to pass through glass tubes, and the tubes were 
then placed in the two glasses, which, as before, 
were connected by the metallic arc. Instead of wa- 
ter, however, both the tubes and glasses were filled 
with an infusion of red cabbage, which held a neu- 
tral salt in solution- As soon as the electricity was 
put in motion, the neutral salt, in each tube and 
glass, was decomposed ; and the effects were at once 
conspicuous on the vegetable infusion. For, on the 
side connected with the positive end of the battery, 
the fluid in the tube was reddened ; while, in the 
glass of the same side, it was rendered green. On 
the contrary, the fluid in the tube connected with the 
negative side was green, and in the glass of the same 
side it was red. Hence, decomposition had taken 
place on each side ; and while the positive pole of the 
battery attracted, as usual, the acid, which reddened 
the infusion in the tube of that side, the negative ox- 
tremity of the arc attracted the alkali in the glass be- 
low, and changed its fluid to a green ; and, by the 
opposite electricities of the respective wires, reverse 
effects were produced in the fluids of the tube and 
