new fact with eagerness, and
investigate it with untiring enthusiasm. It was a sad day for the frogs
of the Pope's dominions when Signora Galvani observed those two naked
legs fly apart and crook themselves with so much animation. There was
slaughter in the swamps of Bologna for many a month thereafter. For
mankind, however, it was a day to be held in everlasting remembrance,
since it was then that was taken the first step toward the galvanic
battery!

As fortune favors the brave, so accident aids the ingenious. After
Professor Galvani had touched the muscles and nerves of many frogs with
the spark drawn from the electrical machine, another accident occurred
which led directly to the discovery of the galvanic battery. Having
skinned a frog, he chanced to hang it by a _copper_ hook upon an _iron_
nail; and thus, without knowing it, he brought together the elements of
a battery,--two metals and a wet frog. His object in hanging up this
frog was to see if the electricity of the atmosphere would produce any
effects, however slight, similar to those produced when the spark of
the machine was applied to the creature. It did not. After watching his
frog awhile, the Professor was proceeding to take it down, and while in
the act of doing so the legs were convulsed! Struck with this
occurrence, he replaced the frog, took it down again, put it back, took
it down, until he discovered that, as often as the damp frog (still
hanging upon its copper hook) touched the iron nail, the contraction of
the muscles took place, as if the frog had been touched by a conductor
connected with an electrical machine. This experiment was repeated
hundreds of times, and varied in as many ways as mortal ingenuity could
devise. Galvani at length settled down upon the method following: he
wrapped the nerves taken from the loins of a frog in a leaf of tin, and
placed the legs of the frog upon a plate of copper; then, as often as
the leaf of tin was brought in contact with the plate of copper, the
legs of the frog were convulsed.

People regard Charles Lamb's story of the discovery of roast pig as a
most extravagant and impossible fiction; but, really, Professor Galvani
comported himself very much in the manner of that great discoverer. It
was no more necessary to employ the frog's nerves in the production of
the electricity, than it was necessary to burn down a house in roasting
pig for dinner. The poor frog contributed nothing to it but his
dampness,-