he polished
coating of the surface of the plate has been removed. It is evident from
this that an even pressure is necessary to produce an evenly bitten
line. Do not touch the ground with your hands while drawing. Rest your
hand on three or four thicknesses of soft blotting-paper. When you
desire to shift the paper, _lift it_, and _never draw it_ over the
ground. Hold the point, not slantingly like a pencil, but as near as
possible perpendicularly. The point is a hard instrument, with which you
cannot produce a swelling line, as with a pencil or a pen. Therefore
your only aim must be an _even_ line, produced by _even pressure_. The
minute threads of ground thrown up by the point you must remove with
your largest camel's-hair brush; otherwise they may clog your lines.
Before commencing to draw read the description of Pl. A given under the
heading "Description of Plates."

7. =Preparing the Plate for the Bath.=--If you were to put the plate
into the acid bath in the state in which it is at present, the acid
would corrode the unprotected parts. To prevent this paint the back, and
the corner by which you held the plate while grounding it, and the edges
with stopping-out varnish. If you are not in a hurry (_and it is always
best not to be in a hurry_), let the varnish dry over night; if you
cannot wait so long an hour will be sufficient for drying. While the
plate is drying you may lay it, face downward, on a little pile of soft
paper, made up of pieces smaller than the plate, so that the paper may
not touch the varnished edges.

8. =The Bath.=--The preparation of the bath is next in order. Ascertain
the capacity of the dish or tray you are going to use by pouring water
into it to fill it to half its height, and then measuring the water.
Pour _one half_ of this quantity of water back into the tray, and add to
it the same quantity of nitric acid, stirring the mixture well with a
glass rod, or a bit of glass, or a bird's feather, if you happen to have
one, or in default of all these with a bit of stick. The mixing of water
and acid induces chemical action, and this produces heat. The bath must
therefore be allowed to cool half an hour or so, before the plate is put
into it. Nitric acid being a corrosive and poisonous fluid, it is well
to use some care in handling it. Otherwise it may bite holes into your
clothing, and disfigure your hands, as before noted. By the side of your
bath have a large vessel filled with clean water,