he follows the subject through its various channels he
will learn that there is a common source of all things; a manifestation
common to all matter, and that all substances in nature are linked
together in a most wonderful way.

An impulse must be given to a boy's training. The time is past for the
rule-and-rote method. The rule can be learned better by a manual
application than by committing a sentence to memory.

In the preparation of this book, therefore, I have made practice and
work the predominating factors. It has been my aim to suggest the best
form in which to do the things in a practical way, and from that work,
as the boy carries it out, to deduce certain laws and develop the
principles which underlie them. Wherever it is deemed possible to do so,
it is planned to have the boy make these discoveries for himself, so as
to encourage him to become a thinker and a reasoner instead of a mere
machine.

A boy does not develop into a philosopher or a scientist through being
told he must learn the principles of this teaching, or the fundamentals
of that school of reasoning. He will unconsciously imbibe the spirit and
the willingness if we but place before him the tools by which he may
build even the simple machinery that displays the various electrical
manifestations.

CHAPTER I

THE STUDY OF ELECTRICITY. HISTORICAL

There is no study so profound as electricity. It is a marvel to the
scientist as well as to the novice. It is simple in its manifestations,
but most complex in its organization and in its ramifications. It has
been shown that light, heat, magnetism and electricity are the same, but
that they differ merely in their modes of motion.

FIRST HISTORICAL ACCOUNT.--The first historical account of electricity
dates back to 600 years B. C. Thales of Miletus was the first to
describe the properties of amber, which, when rubbed, attracted and
repelled light bodies. The ancients also described what was probably
tourmaline, a mineral which has the same qualities. The torpedo, a fish
which has the power of emitting electric impulses, was known in very
early times.

From that period down to about the year 1600 no accounts of any
historical value have been given. Dr. Gilbert, of England, made a number
of researches at that time, principally with amber and other materials,
and Boyle, in 1650, made numerous experiments with frictional
electricity.

Sir Isaac Newton also took up the subject at about the