_clamped_ to a table of a convenient height,
and a sheet of paper, one edge of which is put under the piece A, will
be held fast to the table.

The index P is to be set (at pleasure) with it sharp point to any
part of an object which the eye sees through E, the eye-piece.

The machine is now to be doubled as in Fig. 2, taking care that the
index be not disturbed; the point, which was before perpendicular,
will then approach the paper horizontally, and the place to which it
points on the paper, must be marked with a pencil. The machine must be
again unfolded, and another point of the object is to be ascertained
in the same manner as before; the space between these points may be
then connected with a line; fresh points should then be taken, marked
with a pencil, and connected with a line; and so on successively,
until the whole object is delineated.

Besides the common terms of art, the technical terms of science
should, by degrees, be rendered familiar to our pupils. Amongst these
the words Space and Time occur, as we have observed, the soonest, and
are of the greatest importance. Without exact definitions, or abstract
reasonings, a general notion of the use of these terms may be
inculcated by employing them frequently in conversation, and by
applying them to things and circumstances which occur without
preparation, and about which children are interested, or occupied.
"There is a great space left between the words in that printing." The
child understands, that _space_ in this sentence means white paper
between black letters. "You should leave a greater space between the
flowers which you are planting"--he knows that you mean more _ground_.
"There is a great space between that boat and the ship"--space of
water. "I hope the hawk will not be able to catch that pigeon, there
is a great space between them"--space of air. "The men who are pulling
that sack of corn into the granary, have raised it through half the
space between the door and the ground." A child cannot be at any loss
for the meaning of the word space in these or any other practical
examples which may occur; but he should also be used to the word space
as a technical expression, and then he will not be confused or stopped
by a new term when employed in mechanics.

The word _time_ may be used in the same manner upon numberless
occasions to express the duration of any movement which is performed
by the force of men, or horses, wind, water, or any mechanical p