g one leg in one hand and the other leg in the
other hand (between the forefinger and thumb), pushing and pulling them
sideways, any motion in that direction being sufficient to condemn the
instrument. It is safest and best to have the two legs of the bow-pen
and pencil made from one piece of metal, and not of two separate pieces
screwed together at the top, as the screw will rarely hold them firmly
together. The points should be long and fine, and as round as possible.
In very small instruments separate points that are fastened with a screw
are objectionable, because, in very small circles, they hide the point
and make it difficult to apply the instrument to the exact proper point
or spot on the drawing.

The joints of the large bow or circle-pen should also be somewhat stiff,
and quite free from side motion, and the extension piece should be
rigidly secured when held by the screw. It is a good plan in purchasing
to put in the extension piece, open the joint and the pen to their
fullest, and draw a circle, moving the pen in one direction, and then
redraw it, moving it in the other direction, and if one line only
appears and that not thickened by the second drawing, the pen is a good
one.

The lead pencil should be of hard lead, and it is recommended that they
be of the H, H, H, H, H, H, in the English grades, which corresponds to
the V, V, H, of the Dixon grade. The pencil lines should be made as
lightly as possible; first, because the presence of the lead on the
paper tends to prevent the ink from passing to the paper; and, secondly,
because in rubbing out the pencil lines the ink lines are reduced in
blackness and the surface of the paper becomes roughened, so that it
will soil easier and be harder to clean. In order to produce fine pencil
lines without requiring a very frequent sharpening of the pencil it is
best to sharpen the pencil as in Figures 7 and 8, so that the edge shall
be long in the direction in which it is moved, which is denoted by the
arrow in Figure 7. But when very fine work is to be done, as in the case
of Patent Office drawings, a long, round point is preferable, because
the eye can see plainer just where the pencil will begin to mark and
leave off; hence the pencil lines will not be so liable to overrun.

[Illustration: Fig. 7.]

[Illustration: Fig. 8.]

In place of the ordinary wood-covered lead pencils there may be obtained
at the drawing material stores pencil holders for holding the fine