all softness of line; being easily
frangible, it would be ridiculous to give it sharp edges, so that a
blunt and massive rendering of graceful gesture will be its natural
function: but as it can be pinched, or pulled, or thrust in a moment
into projection which it would take hours of chiseling to get in stone,
it will also properly be used for all fantastic and grotesque form, not
involving sharp edges. Therefore, what is true of chalk and charcoal,
for painters, is equally true of clay, for sculptors; they are all most
precious materials for true masters, but tempt the false ones into fatal
license; and to judge rightly of terra-cotta work is a far higher reach
of skill in sculpture-criticism than to distinguish the merits of a
finished statue.

157. We have, secondly, work in bronze, iron, gold, and other metals;
in which the laws of structure are still more definite.

All kinds of twisted and wreathen work on every scale become delightful
when wrought in ductile or tenacious metal; but metal which is to be
_hammered_ into form separates itself into two great divisions--solid,
and flat.

A. In solid metal-work, _i.e._, metal cast thick enough to resist
bending, whether it be hollow or not, violent and various projection may
be admitted, which would be offensive in marble; but no sharp edges,
because it is difficult to produce them with the hammer. But since the
permanence of the material justifies exquisiteness of workmanship,
whatever delicate ornamentation can be wrought with rounded surfaces may
be advisedly introduced; and since the color of bronze or any other
metal is not so pleasantly representative of flesh as that of marble, a
wise sculptor will depend less on flesh contour, and more on picturesque
accessories, which, though they would be vulgar if attempted in stone,
are rightly entertaining in bronze or silver. Verrocchio's statue of
Colleone at Venice, Cellini's Perseus at Florence, and Ghiberti's gates
at Florence, are models of bronze treatment.

B. When metal is beaten thin, it becomes what is technically called
'plate,' (the _flattened_ thing,) and may be treated advisably in two
ways: one, by beating it out into bosses, the other by cutting it into
strips and ramifications. The vast schools of goldsmiths' work and of
iron decoration, founded on these two principles, have had the most
powerful influences over general taste in all ages and countries. One of
the simplest and most interesting elementa