needle, which gives
modelling to the etching. In this case, also, one or several points may
be used. The simplest manner is that in which only one point is used.
The stopping-out, and consequently the biting, is done in large masses.
(See Pl. V. Fig. 1.)

70. =Biting with Stopping-out.--Several Points.=--As a very simple
example let us take a case in which it is necessary to have certain very
closely lined passages in a foreground alongside of very coarse ones.
In that case the first, or close, lines must be etched very delicately,
while the whole force of the biting must be brought to bear on the
latter (see Pl. IV. Fig. 2). In the same way the values of two different
objects may be equilibrated; by employing close lines slightly bitten in
the one case, and spaced lines more deeply bitten in the other. Biting
with stopping-out, combined with the work of several points, requires
more attention and discernment than any other.

If the first biting is not successful, the plate is revarnished, and the
work of repairing and correcting commences.

Summing up the advantages offered by these various means, you will see
what results the combination of the work of one or of several points
with partial biting may be made to yield, either in giving to objects
their various values, their natural color, and their modelling, or in
disposing them in space, and thus producing the harmonious gradation of
the several distances.

71. =Necessity of Experimenting.=--If you will now call to mind our
preceding operations, and will hold them together with the explanations
just given, you will be able to appreciate them in their totality. The
necessity of arriving at truth of expression, with nothing to guide you
but these rules, which are influenced by a variety of conditions, will
compel you to experiment for yourself, with special reference to the
combination of _the surrounding temperature, the strength of the acid,
the number of partial bitings, the pressure of the point, the different
thicknesses of the points_, and _the various kinds of work that can be
done with them_, on the one hand; and on the other, with regard to _the
length of the bitings_. If you are called upon to imitate a given object
very closely, you must proceed rationally, and your work must be
accompanied by continual reflection. To familiarize yourself with these
delicate operations, you must experiment for yourself; don't complain if
you spoil a few plates; you will