rubbing
with charcoal-paste and a bit of fine linen. The burnisher alone would
give too much polish to the copper; in printing the ink would leave no
tint on the plate in these spots, and the traces of the burnisher would
show as white marks in the proofs. To avoid this, the copper must be
restored to its natural state.[14]

"What would happen," asks another of my pupils, "if these little holes
occurred in a sky or in some other closely worked passage? Here is a
plate in which this accident has befallen some clouds and part of the
ground. What shall I do?"

To begin with, let me tell you for your future guidance that this
accident would not have happened if you had waited for the drying of the
ground with which you covered this sky after you had bitten it. The
acid, which never loses an opportunity given it by mismanagement or
inattention, worked its way unbeknown to you through the soft varnish in
the clouds as well as in the ground, and went on a spree at your
expense. Remember that nitric acid is very selfish; it insists that it
shall always be uppermost in your mind, and all your calculations must
take this demand into account; its powers, creative as well as
destructive, are to be continually dreaded; it likes to see you occupy
yourself with it continually, watchfully, and with fear. If you turn
your back to it, it plays you a trick, and thus it has punished you for
neglecting it for a moment.

"Thank you. But you are acting the part of La Fontaine's schoolmaster,
who moralized with the pupil when he had fallen into the water."

63. =Planing out Faulty Passages.=--And that did not help him out. You
are right. Well, you must go to some skilful copper-planer,[15] who will
work away at the spoiled part of your plate with scraper and burnisher
and charcoal, until he has restored the copper to its virgin state; then
all you've got to do will be to do your work over again.

"That is rather a blunt way of settling the question. Seeing that we are
about to cut into the flesh after this fashion, might it not be as well
to have the whole of the sky taken out altogether? I am not satisfied
with it, any way."

Certainly. By the same process the planer can remove every thing, up to
the outlines of the trees and the figures in your plate; he will cut out
any thing you want, and yet respect all the outlines, if you will only
indicate your wishes on a proof. In this passage, where you see deep
holes, scraper and charcoal w