50. How Chemistry Made Friends with Electricity
It was an odd thing, at first glance, for a respectable man held in high esteem by all his
friends, to occupy himself with.
First he prepared little metallic discs. Dozens and dozens of discs, copper and zinc
ones. Then he cut up several sponges into round slices and soaked them in salt water.
After this he began to stack the pieces on top of each other in much the same way as a
child builds a pyramid, but, observing a certain sequence: a copper disc, a slice of
sponge, a zinc disc. And he repeated this sequence many times. In a word, as long as he
could keep the stack from falling down.
The man touched the top of his original structure with a moistened finger, and jerked
his hand away immediately: he had received what we would now call a substantial
electric shock.
That was how in 1800 the famous Italian physicist Alessandro Volta invented the
galvanic cell, a chemical source of current. The electricity appeared in the "volta column"
as a result of chemical reactions.
This marked the birth of new branch of science called electrochemistry.
Scientists acquired an instrument by means of which they could produce electric
current over a considerable length of time. The current would continue to flow until the
chemical process in the "volta column" stopped.
It appeared interesting to find out how electricity would act on different substances.
Two Englishmen, Carlisle, a physician, and Nicholson, an engineer, decided to start
with water. By that time chemists had sufficient grounds to state that water consisted of
hydrogen and oxygen. But somehow they had been unable to obtain conclusive proof.
Carlisle and Nicholson used an electric battery consisting of 17 voltaic cells. It gave a
very strong current. And the water began to decompose vigorously into two gases,
hydrogen and oxygen; in other words, electrolysis set in. That is what we call the process
of decomposition of substances by electricity.