solved in cold
water. Any good chemist will sell this, but its purity is a matter of
great importance, for you want the maximum of adhesiveness with the
minimum of the material.

Mix the colour well up with the knife; then take one of those
long-haired sable brushes, which are called "riggers" (fig. 19), and
which all artists'-colourmen sell, and fill it with the colour, diluting
it with enough water to make it quite thin. Do not dilute all the
pigment; keep most of it in a tidy lump, merely moist, as you ground it
and not further wetted, at the corner of your slab; but always keep a
portion diluted in a small "pond" in the middle of your palette.

[Illustration: Fig. 18.]

_How to Fill the Brush with Pigment._--Now you must note that this is a
heavy powder floating free in water, therefore it quickly sinks to the
bottom of your little "pond." _Each time you fill your_ _brush you must
"stir up the mud_," for the "mud" is what you want to get in your brush,
and not only so, but you want to get your brush _evenly full_ of it from
tip to base, therefore you must splay out the hairs flat against the
glass, till all are wet, and then in taking it off the palette,
"twiddle" it to a point quickly. This takes long to describe, but it
does not take a couple of seconds to do. You must have the patience to
spend so much pains on it, and even to fill the brush very often, nearly
for each touch; then you will get a clear, smooth, manageable stroke for
your outline, and save time in the end.

[Illustration: FIG. 19.]

_How to Paint in Outline._--Make some strokes (fig. 20) on a piece of
glass and let them dry; some people like them to stick very tight to the
glass, some so that a touch of the finger removes them; you must find
which suits you by-and-by, and vary the amount of gum accordingly; but
to begin, I would advise that they should be just removable by a
moderately hard rub with the finger, rather less hard a rub than you
close a gummed envelope with.

Practise now for a time the making of strokes, large and small, dark and
light, broad and fine; and when you have got command of your tools, set
yourself the task of doing the same thing, _copying an example placed
underneath your bit of glass_. You will find a hand-rest (fig. 21) an
assistance in this.

[Illustration: FIG. 20.]

It is difficult to give any list of examples suitable for this stage of
glass, but the kind of line employed on the best _heraldry_ is always