ray, of whatever depth we want,
with a pointed instrument. Take any finely pointed steel pen (one of
Gillott's lithographic crowquills is best), and a piece of quite smooth,
but not shining, note-paper, cream laid, and get some ink that has stood
already some time in the inkstand, so as to be quite black, and as thick
as it can be without clogging the pen. Take a rule, and draw four
straight lines, so as to inclose a square, or nearly a square, about as
large as _a_, Fig. 1. I say nearly a square, because it does not in the
least matter whether it is quite square or not, the object being merely
to get a space inclosed by straight lines.

8. Now, try to fill in that square space with crossed lines, so
completely and evenly that it shall look like a square patch of gray
silk or cloth, cut out and laid on the white paper, as at _b_. Cover it
quickly, first with straightish lines, in any direction you like, not
troubling yourself to draw them much closer or neater than those in the
square _a_. Let them quite dry before retouching them. (If you draw
three or four squares side by side, you may always be going on with one
while the others are drying.) Then cover these lines with others in a
different direction, and let those dry; then in another direction still,
and let those dry. Always wait long enough to run no risk of blotting,
and then draw the lines as quickly as you can. Each ought to be laid on
as swiftly as the dash of the pen of a good writer; but if you try to
reach this great speed at first, you will go over the edge of the
square, which is a fault in this exercise. Yet it is better to do so now
and then than to draw the lines very slowly; for if you do, the pen
leaves a little dot of ink at the end of each line, and these dots spoil
your work. So draw each line quickly, stopping always as nearly as you
can at the edge of the square. The ends of lines which go over the edge
are afterwards to be removed with the penknife, but not till you have
done the whole work, otherwise you roughen the paper, and the next line
that goes over the edge makes a blot.

9. When you have gone over the whole three or four times, you will find
some parts of the square look darker than other parts. Now try to make
the lighter parts as dark as the rest, so that the whole may be of equal
depth or darkness. You will find, on examining the work, that where it
looks darkest the lines are closest, or there are some much darker lines
than else