taken place. Two things are evident to common sense.
One, that the change is organic, and the other that it is
unpremeditated; and therefore, on both grounds, it is a thing to avoid,
which indeed my friend's scientific explanation sufficiently confirms.
It is well, therefore, on all accounts to paint swiftly and
continuously, and to fire as soon as you can; and above all things not
to let the colour lie about getting stale on the palette. Mix no more
for the day than you mean to use; clean your palette every day or nearly
so; work up all the colour each time you set your palette, and do not
give way to that slovenly and idle practice that is sometimes seen, of
leaving a crust of dry colour to collect, perhaps for days or weeks,
round the edge of the mass on your palette, and then some day, when the
spirit moves you, working this in with the rest, to imperil the safety
of your painting.

_How to Know when the Glass is Fired Sufficiently._--This is told by the
colour as it lies in the kiln--that is, in such a kiln that you can see
the glass; but who can describe a colour? You have nothing for this but
to buy your experience. But in kilns that are constructed with a
peephole, you can also tell by putting in a bright iron rod or other
shining object and holding it over the glass so as to see if the glass
reflects it. If the pigment is raw it will (if there is enough of it on
the glass to cover the surface) prevent the piece of glass from
reflecting the rod; but directly it is fired the pigment itself becomes
glossy, and then the surface will reflect.

This is all a matter of practice; nothing can describe the "look" of a
piece of glass that is fired. You must either watch batch after batch
for yourself and learn by experience, or get a good kiln-man to point
out fired and unfired, and call your attention to the slight shades of
colour and glow which distinguish one from the other.

_On Taking the Glass out of the Fire._--And so you take the glass out of
the fire. In the old kilns you take the fire away from the glass, and
leave the glass to cool all night or so; in the new, you remove it and
leave it in moderate heat at the side of the kiln till it is cool enough
to handle, or nearly cold. And then you hold it up and look at it.

CHAPTER VIII

The Second Painting--Disappointment with Fired Work--A False
Remedy--A Useful Tool--The Needle--A Resource of Desperation--The
Middle Course--Use of the Fing