school-room as long as they can, and never cease to think, and seldom to
talk, of their delightful labors.

Unfortunately, there are too many of the former class, and the first
object which, in this work, I shall attempt to accomplish, is to show my
readers, especially those who have been accustomed to look upon the
business of teaching as a weary and heartless toil, how it happens that
it is, in any case, so pleasant. The human mind is always essentially
the same. That which is tedious and joyless to one, will be so to
another, if pursued in the same way, and under the same circumstances.
And teaching, if it is pleasant, animating, and exciting to one, may be
so to all.

I am met, however, at the outset, in my effort to show why it is that
teaching is ever a pleasant work, by the want of a name for a certain
faculty or capacity of the human mind, through which most of the
enjoyment of teaching finds its avenue. Every mind is so constituted as
to take a positive pleasure in the exercise of ingenuity in adapting
means to an end, and in watching the operation of them--in accomplishing
by the intervention of instruments what we could not accomplish
without--in devising (when we see an object to be effected which is too
great for our _direct_ and _immediate_ power) and setting at work some
_instrumentality_ which may be sufficient to accomplish it.

[Illustration: Steam Engine]

It is said that when the steam-engine was first put into operation,
such was the imperfection of the machinery, that a boy was necessarily
stationed at it to open and shut alternately the cock by which the steam
was now admitted and now shut out from the cylinder. One such boy, after