ans of warding
off the evil effects of a natural manifestation of electricity. The
invention, however, had all the effects of a mechanism which turned
electricity to practical account. But with the advent of the new kind of
electricity the age of practical application began.

DAVY AND ELECTRIC LIGHT

Volta's announcement of his pile was scarcely two months old when two
Englishmen, Messrs. Nicholson and Carlisle, made the discovery that
the current from the galvanic battery had a decided effect upon certain
chemicals, among other things decomposing water into its elements,
hydrogen and oxygen. On May 7, 1800, these investigators arranged the
ends of two brass wires connected with the poles of a voltaic pile,
composed of alternate silver and zinc plates, so that the current coming
from the pile was discharged through a small quantity of "New River
water." "A fine stream of minute bubbles immediately began to flow from
the point of the lower wire in the tube which communicated with the
silver," wrote Nicholson, "and the opposite point of the upper wire
became tarnished, first deep orange and then black...." The product of
gas during two hours and a half was two-thirtieths of a cubic inch.
"It was then mixed with an equal quantity of common air," continues
Nicholson, "and exploded by the application of a lighted waxen thread."

This demonstration was the beginning of the very important science of
electro-chemistry.

The importance of this discovery was at once recognized by Sir Humphry
Davy, who began experimenting immediately in this new field. He
constructed a series of batteries in various combinations, with which
he attacked the "fixed alkalies," the composition of which was then
unknown. Very shortly he was able to decompose potash into bright
metallic globules, resembling quicksilver. This new substance he named
"potassium." Then in rapid succession the elementary substances sodium,
calcium, strontium, and magnesium were isolated.

It was soon discovered, also, that the new electricity, like the old,
possessed heating power under certain conditions, even to the fusing of
pieces of wire. This observation was probably first made by Frommsdorff,
but it was elaborated by Davy, who constructed a battery of two thousand
cells with which he produced a bright light from points of carbon--the
prototype of the modern arc lamp. He made this demonstration before the
members of the Royal Institution in 1810. But the practic