uch
more, and the colour gets dark, thick, and oily-looking. Put two
teaspoonfuls of water to the colour you have rubbed down, and mix it
well up with a camel's-hair brush about three quarters of an inch long.

Then take a piece of smooth, but not glossy, Bristol board or
pasteboard; divide it, with your pencil and rule, into squares as large
as those of the very largest chess-board: they need not be perfect
squares, only as nearly so as you can quickly guess. Rest the pasteboard
on something sloping as much as an ordinary desk; then, dipping your
brush into the colour you have mixed, and taking up as much of the
liquid as it will carry, begin at the top of one of the squares, and lay
a pond or runlet of colour along the top edge. Lead this pond of colour
gradually downwards, not faster at one place than another, but as if you
were adding a row of bricks to a building, all along (only building down
instead of up), dipping the brush frequently so as to keep the colour as
full in that, and in as great quantity on the paper, as you can, so only
that it does not run down anywhere in a little stream. But if it should,
never mind; go on quietly with your square till you have covered it all
in. When you get to the bottom, the colour will lodge there in a great
wave. Have ready a piece of blotting-paper; dry your brush on it, and
with the dry brush take up the superfluous colour as you would with a
sponge, till it all looks even.

In leading the colour down, you will find your brush continually go over
the edge of the square, or leave little gaps within it. Do not endeavour
to retouch these, nor take much care about them; the great thing is to
get the colour to lie smoothly where it reaches, not in alternate blots
and pale patches; try, therefore, to lead it over the square as fast as
possible, with such attention to your limit as you are able to give. The
use of the exercise is, indeed, to enable you finally to strike the
colour up to the limit with perfect accuracy; but the first thing is to
get it even, the power of rightly striking the edge comes only by time
and practice; even the greatest artists rarely can do this quite
perfectly.

When you have done one square, proceed to do another which does not
communicate with it. When you have thus done all the alternate squares,
as on a chess-board, turn the pasteboard upside down, begin again with
the first, and put another coat over it, and so on over all the others.
The use