ly spaced lines in this tree in the foreground,
you will risk nothing by giving them a final touch with pure acid. The
strongest accent in the landscape rests on this spot; it determines the
color of the whole. By this application of pure acid we shall get a
vigorous tone, a powerful effect.

I may as well tell you here that it is sometimes advisable to add a
small quantity of pure acid to the bath towards the end of the
operation, so as to increase the activity of the biting on certain parts
of the plate without running into excess. But as the place now under
consideration is restricted, we shall adopt another means, so as to
limit the action of the acid to the given point. See here: I let fall a
few drops; the pure acid eats into the copper with great vehemence; the
metal turns green, and the ebullition subsides. Now take up the
exhausted liquid with a piece of blotting-paper, and let us commence
again. Under these newly added drops of fresh acid, the varnish is ready
to scale off, the lines sputter, and assume a strange yellow color;
these golden vapors announce that the operation is finished.

What follows, is the task of the printer; his press will tell us whether
we have won, or whether we have been mated. Clean the plate with spirits
of turpentine, using your fingers, or with a very clean old rag (calico,
if possible), if you are afraid to soil your hands. Be sure to have the
plate well cleaned, but take care not to scratch it.

The acid, which may be of use hereafter, we will turn into a glass
bottle with a ground stopper, and will store it in some safe place.

CHAPTER IV.

FINISHING THE PLATE.

43. =Omissions.--Insufficiency of the Work so far done.=--The result you
have obtained, I tell my pupil, as he shows a proof of the _first state_
of his plate to me, is not final. Your work needs a few retouches and
slight modifications, not counting the little irregularities which I had
foreseen, and which it will be easy enough to repair. We will proceed in
order. (See Pl. I^_a_). To commence with, here are certain parts which
are sufficiently bitten, and which, nevertheless, are indecisive in
tone, and do not hold their place. I allude to the columns and to the
trees in the further distance; one feels that there is something wanting
there, which must be added. You must, therefore, re-cover your plate, in
the manner already known to you, either with transparent ground, or with
ordinary etching-ground, jus