n: Fig. 22.]

[Illustration: Fig. 23.]

[Illustration: Fig. 24.]

[Illustration: Fig. 25.]

[Illustration: Fig. 26.]

Each of the legs should be of equal thickness at the pen-point edge, so
that when closed together the point will be in the middle of the edge.
The width and curve of each individual point should be quite equal, and
the easiest method of attaining this end is as follows:

Take a small slip of Arkansas oil-stone, and with the pen-points closed
firmly by the screw trim the pen-edges to the required curve as shown at
A, Figure 17, making the curve as even as possible. Then stone the faces
until this curve is brought up to a sharp edge at the point between the
two pen-legs forming the point.

Next take a piece of 000 French emery paper, lay it upon some flat body
like the blade of a square, and smooth the curve of the edge enough to
take off the fine, sharp edge left by the oil-stone; then apply the
outside flat faces of the pen to the emery paper again, bringing the
pen-edge up sharp.

The emery paper will simply have smoothed and polished the surfaces,
still leaving them too sharp, so sharp as to cut the paper, and to take
off this sharp edge (which must first be done on the inside faces) open
the pen-points as wide as the screw will permit. Then wrap one thickness
of the emery paper upon a thin blade, as upon a drawing-triangle, and
pass the open pen-points over it, and move the instrument endwise,
taking care to keep the inside face level with the surface of the emery
paper, so that the pen-points shall not cut through. Next close the
pen-points with the screw until they nearly, but not quite, touch, and
sweep the edge of the pen-point along the emery paper under a slight
pressure, so moving the handle that at each stroke the whole length
around the curved end of the pen will meet the emery surface. During
this motion the inside faces of the pen-point must be held as nearly
vertical as possible, so as to keep the two halves of the pen-point
equal.

The pen is now ready for use, and will draw a fine and clean line.

It is not usual to employ emery paper for the purpose indicated, but it
will be found very desirable, since it leaves a smoother surface and
edge than the oil-stone alone.

Circle-pens are more difficult to put in order than the straight-line
pen, especially those for drawing the smallest circles, which cannot be
well drawn unless the pen is of the precise right shape and in the b