which are called
"guillotines" for an obvious reason. In binding some books, which it is
desired to preserve with wide margins, only a mere shaving is taken off
the head, so as to leave it smooth at the top, letting the front and tail
leaves remain uncut. But in case of re-binding much-used books, the edges
are commonly so much soiled that trimming all around may be required, in
order that they may present a decent appearance. Yet in no case should
the binder be allowed to cut any book deeply, so as to destroy a good,
fair margin. Care must also be taken to cut the margins evenly, at right
angles, avoiding any crooked lines.

After cutting the book comes "rounding," or giving the back of the book a
curved instead of its flat shape. This process is done with the hand, by
a hammer, or in a rounding press, with a metallic roller. Before
rounding, the back of the book is glued up, that is, receives a coating
of melted glue with a glueing brush, to hold the sections together, and
render the back firm, and a thorough rubbing of the back with hot glue
between the sections gives strength to the volume.

Next comes the treatment of the edges of the book, hitherto all white, in
order to protect them from showing soil in long use. Sometimes (and this
is the cheaper process) the books are simply sprinkled at the edges with
a brush dipped in a dark fluid made of burnt umber or red ochre, and
shaken with a quick concussion near the edges until they receive a
sprinkle of color from the brush. Other books receive what is called a
solid color on the edges, the books being screwed into a press, and the
color applied with a sponge or brush.

But a marbled edge presents a far more handsome appearance, and should
harmonize in color and figure with the marbled paper of the end leaves.
Marbling, so called from its imitation of richly veined colored marble,
is staining paper or book edges with variegated colors. The process of
marbling is highly curious, both chemically and aesthetically, and may be
briefly described. A large shallow trough or vat is filled with prepared
gum water (gum-tragacanth being used); on the surface of this gum-water
bright colors, mixed with a little ox-gall, to be used in producing the
composite effect aimed at in the marbling are thrown or sprinkled in
liquid form. Then they are deftly stirred or agitated on the surface of
the water, with an implement shaped to produce a certain pattern. The
most commonly used one