in which to wash the
plate when it is withdrawn from the bath, and your fingers in case you
should soil them with acid.

9. =Biting and Stopping Out.=--The bath having been prepared, and the
varnish on the back and edges of the plate having dried sufficiently,
lay the plate on the plate-lifter, face upward, and lift it into the
bath. In a few minutes, in hot weather in a few seconds, the acid will
begin to act on the copper. This is made evident to the eye by the
bubbles which collect in the lines, and to the nose by the fumes of
nitrous acid which the bath exhales. The bubbles must be removed by
gently brushing them out of the lines with a brush or the vane of a
feather; the fumes it is best not to inhale, as they irritate the
throat. After the biting has gone on for three minutes in warm, or for
five minutes in cold weather, lift the plate out of the bath into the
vessel filled with water. Having washed it well, so as to remove all
traces of the acid, lay it on a piece of blotting-paper, and take up the
moisture from the face by gently pressing another piece of the same
paper against it. Then fan the plate for some minutes to make sure that
it is absolutely dry. If you have a pair of bellows you may dispense
with the blotting-paper as well as with the fanning. The lines on the
plate, having all bitten for the same length of time, are now all of
about the same depth, and if the plate were cleaned and an impression
taken from it, they would all appear of about the same strength, the
only difference being that produced by difference in spacing and in the
size of the needles. This is the point where the stopping-out varnish
comes in. With a fine camel's-hair brush _stop out_, that is to say,
paint over with stopping-out varnish, those lines or parts of lines
which are to remain as they are. If the varnish should be too thick to
flow easily from the brush, mix a small quantity of it in a paint
saucer, or on a porcelain slab, or a piece of glass, with a few drops of
benzine. The varnish, however, must not be too thin, as in that case it
will run in the lines, and will fill them where you do not wish them to
be filled. If it is of the right consistency, you can draw a clean and
sharp line across the etched lines without danger of running. When you
have laid on your stopping-out varnish, fan it for some minutes until it
has dried sufficiently not to adhere to the finger when lightly touched.
Then introduce the plate into the