The letter D you shall make thus: Divide its square by the perpendicular
or vertical line g. h. and by the horizontal line e. f. into four small
squares, and call their point of intersection i.: then draw the broader
limb of the letter from the side a. b. downwards, to meet the side c. d.
and at the distance of its own width from a. c.; and produce the limb at
top and bottom to a sharp point at the angles a. and c. as was shown
above in B; using the same method in all straight limbs in the remaining
letters. Next you are to produce from this limb two narrower tracts
horizontally, and from these are to be described the circular arcs of
the letter between the line a. b. at top and the line c. d. at bottom,
and extending as far as the perpendicular g. h.; next, with your compass
join g. f. h. Then, in the line e. f. lay off a portion equal in breadth
to the widest limb of the letter, at the point k.; next, set one foot of
your compass on k. and let the other cut the said line e. f. in l.; let
this be the immovable leg of your compass, and with the other, beginning
from k., describe internally, to the narrower transverse limbs, an arc
which shall touch both, completing your acute angle above, but rounding
out the lower one by a circular arc of the same diameter as the one by
which you sharpened your exterior subtending angle.
Another method.
You may make the round limb of the same D in another fashion; namely, as
a pen naturally would, broader above than below. For this, draw the
diagonal c. b. and describe your exterior arc as before; but to describe
the interior, in the line c. b. take a point m. lower down than i. and
distant from it the width of the broader limb, and without altering your
compass describe an interior line; but where the limb must needs be
narrower, there you are to accommodate it with your hand, both below and
above, as in the following cut.
[Illustration: D]