fine
time the wandering tendrils are enclosed by limits approximately
rectilinear, and in gracefullest branching often detach themselves from
the right line only by curvature of extreme severity.

174 Since the darkness and extent of shadow by which the sculpture is
relieved necessarily vary with the depth of the recess, there arise a
series of problems, in deciding which the wholesome desire for emphasis
by means of shadow is too often exaggerated by the ambition of the
sculptor to show his skill in undercutting. The extreme of vulgarity is
usually reached when the entire bas-relief is cut hollow underneath, as
in much Indian and Chinese work, so as to relieve its forms against an
absolute darkness; but no formal law can ever be given; for exactly the
same thing may be beautifully done for a wise purpose, by one person,
which is basely done, and to no purpose, or to a bad one, by another.
Thus, the desire for emphasis itself may be the craving of a deadened
imagination, or the passion of a vigorous one; and relief against
shadow may be sought by one man only for sensation, and by another for
intelligibility. John of Pisa undercuts fiercely, in order to bring out
the vigour of life which no level contour could render; the Lombardi of
Venice undercut delicately, in order to obtain beautiful lines, and
edges of faultless precision; but the base Indian craftsmen undercut
only that people may wonder how the chiselling was done through the
holes, or that they may see every monster white against black.

175. Yet, here again we are met by another necessity for discrimination.
There may be a true delight in the inlaying of white on dark, as there
is a true delight in vigorous rounding. Nevertheless, the general law is
always, that, the lighter the incisions, and the broader the surface,
the grander, caeteris paribus, will be the work. Of the structural terms
of that work you now know enough to understand that the schools of good
sculpture, considered in relation to projection, divide themselves into
four entirely distinct groups:--

1st. Flat Relief, in which the surface is, in many places,
absolutely flat; and the expression depends greatly on the
lines of its outer contour, and on fine incisions within
them.

2nd. Round Relief, in which, as in the best coins, the
sculptured mass projects so as to be capable of complete
modulation into form, but is not anywhere undercut. The
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