they call him a wild horse because he bolts, or a thief because he
lurks! We prefer to call him a Spark, because in that form only is he
visible--at least when handled by man.

Talking of that, it was not until the last century that master minds
found out how to catch and handle our Spark. In all the previous
centuries he had been roaming gaily about the world in perfect freedom;
sometimes gliding silently to and fro like an angel of light; sometimes
leaping forth with frightful energy in the midst of raging tempest, like
a destructive demon--ripping, rending, shattering all that attempted to
arrest his course. Men have feared and shunned him since the beginning
of time, and with good reason, for he has killed many of the human race.

But although uncaught and untamed by them, our Spark was not altogether
unknown to the ancients. So far back as the year 600 before the
Christian era, Thales, one of the Greek sages, discovered that he hid
himself in amber, a substance which in Greek is named _electron_--hence
his name Electricity; but the ancients knew little about his character,
though Thales found that he could draw him from his hiding-place by
rubbing him with silk and some other substances. When thus rubbed he
became attractive, and drew light creatures towards him--not unlike
human sparks! He also showed himself to be fickle, for, after holding
these light creatures tight for a brief space, he let them go and
repelled them.

It was not till the days of good Queen Bess, towards the end of the
sixteenth century, that a Dr Gilbert discovered that the wild fellow
lay lurking in other substances besides amber--such as sulphur, wax,
glass, etcetera. It is now known that Electricity permeates all
substances more or less, and only waits to be roused in order to exhibit
his amazing powers. He is fond of shocking people's feelings, and has
surprised his pursuers rather frequently in that way. Some of them,
indeed, he has actually shocked to death!

It would take a huge volume to give a detailed account of all the
qualities, powers, and peculiarities of this wild Spark. We will just
touch on a few facts which are necessary to the elucidation of our tale.

A great event in the world's history happened in the year 1745. It was
nothing less than the capture and imprisonment of wild, daring, dashing
Electricity. To the Dutch philosophers belongs the honour of catching
him. They caught him--they even bottled him, l