g of words, and the structure of common
domestic implements, to children, is the sure and effectual method of
preparing the mind for the acquirement of science.

The ancients, in learning this species of knowledge, had an advantage
of which we are deprived: many of their terms of science were the
common names of familiar objects. How few do we meet who have a
distinct notion of the words radius, angle, or valve. A Roman peasant
knew what a radius or a valve meant, in their original signification,
as well as a modern professor; he knew that a valve was a door, and a
radius a spoke of a wheel; but an English child finds it as difficult
to remember the meaning of the word angle, as the word parabola. An
angle is usually confounded, by those who are ignorant of geometry and
mechanics, with the word triangle, and the long reasoning of many a
laborious instructer has been confounded by this popular mistake. When
a glass pump is shown to an admiring spectator, he is desired to watch
the motion of the valves: he looks "above, about, and underneath;"
but, ignorant of the word _valve_, he looks in vain. Had he been
desired to look at the motion of the little doors that opened and
shut, as the handle of the pump was moved up and down, he would have
followed the lecturer with ease, and would have understood all his
subsequent reasoning. If a child attempts to push any thing heavier
than himself, his feet slide away from it, and the object can be moved
only at intervals, and by sudden starts; but if he be desired to prop
his feet against the wall, he finds it easy to push what before eluded
his little strength. Here the use of a fulcrum, or fixed point, by
means of which bodies may be moved, is distinctly understood. If two
boys lay a board across a narrow block of wood, or stone, and balance
each other at the opposite ends of it, they acquire another idea of a
centre of motion. If a poker is rested against a bar of a grate, and
employed to lift up the coals, the same notion of a centre is recalled
to their minds. If a boy, sitting upon a plank, a sofa, or form, be
lifted up by another boy's applying his strength at one end of the
seat, whilst the other end of the seat rests on the ground, it will be
readily perceived by them, that the point of rest, or centre of
motion, or fulcrum, is the ground, and that the fulcrum is not, as in
the first instance, between the force that lifts, and the thing that
is lifted; the fulcrum is at one