tals_]

SUGGESTIONS IN DRAWING.--As in the use of all other tools, so with the
drawing instrument, it must be kept in proper order. If the points are
too fine they will cut the paper; if too blunt the lines will be ragged.
In whetting the points hold the pen at an angle of 12 degrees. Don't
make too long an angle or slope, and every time you sharpen hold it at
the same angle, so that it is ground back, and not at the point only.

[Illustration: _Fig. 119. Using the Protractor._]

HOLDING THE PEN.--The drawing pen should be held as nearly vertical as
possible. Use the cleaning rag frequently. If the ink does not flow
freely, after you have made a few strokes, as is frequently the case,
gently press together the points. The least grit between the tines will
cause an irregular flow.

INKS.--As prepared liquid inks are now universally used, a few
suggestions might be well concerning them. After half the bottle has
been used, add a half teaspoonful of water, shake it well, and then
strain it through a fine cotton cloth. This will remove all grit and
lint that is sure to get into the bottle however carefully it may be
corked.

[Illustration: _Fig. 120. Section Lining Metals_]

TRACING CLOTH.--It is preferable to use the dull side of the tracing
cloth for the reasons that, as the cloth is rolled with the glossy side
inside, the figure when drawn on the other side will be uppermost, and
will thus lie flat; and on the other hand, the ink will take better on
the dull side.

If the ink does not flow freely, use chalk, fine pumice stone, or talc,
and rub it in well with a clean cloth, and then wipe off well before
beginning to trace.

DETAIL PAPER.--The detail paper, on which the drawing is first made in
pencil, should show the figure accurately, particularly the points where
the bow pen are to be used, as well as the measurement points for the
straight lines.

HOW TO PROCEED.--Make the circles, curves, and irregular lines first,
and then follow with the straight lines. Where the point of the circle
pen must be used for a large number of lines, as, for instance, in
shading, the smallest circles should be made first, and the largest
circles last, because at every turn the centering hole becomes larger,
and there is liability to make the circles more or less irregular. Such
irregularity will not be so noticeable in the large curves as in the
smaller ones.

INDICATING MATERIAL BY THE SECTION LINES.--In section lining diff