a bad one at B.

[Illustration: FIG. 69.]

[Illustration: FIG. 70.]

The next operation will be to fill in the board and mitre the corners.
To fill in the boards, a piece of paper as thick as the turn-in of the
leather (engineer's cartridge paper answers very well) should be cut a
little smaller than the board, with one edge cut straight; then with
the straight edge adjusted to the back of the board, and a weight
placed on the centre, the paper is marked round with dividers set to
the intended width of the turn-in of the leather. Then with a sharp
knife, paper and leather may be cut through together. The paper should
then be marked to show its position on the board, and the ragged edges
of the leather trimmed off. This will leave an even margin of leather
on three sides of the inside of the board, and a piece of paper that
will exactly fit the remaining space. The corners must next be
mitred. To do this, both thicknesses of leather are cut through from
the corner of the board to the corner of the inside margin. The knife
should be held slightly slanting to make a cut, as shown at fig. 70.
The corners should then be thoroughly damped, and the overlapping
leather from both sides removed, leaving what should be a neat and
straight join. If the leather at the extreme corner should prove to
be, as is often the case, too thick to turn in neatly, the corners
should be opened out and the leather pared against the thumb nail, and
then well pasted and turned back again. The extreme corner may be
slightly tapped on the stone with a hammer, and the sides rubbed with
a folder, to ensure squareness and sharpness. When all four corners
have been mitred, the filling in papers can be pasted in. As they will
probably stretch a little with the paste, it will be well to cut off a
slight shaving, and they should then fit exactly. When the boards have
been filled in and well rubbed down, the book should be left for some
hours with the boards standing open to enable the filling-in papers to
draw the boards slightly inwards to overcome the pull of the leather.

In cases where there are leather joints the operation is as follows:
The waste end paper is removed, and the edge of the board and joint
carefully cleaned from glue and all irregularities, and if, as is most
likely, it is curved from the pull of the leather, the board must be
tapped or ironed down until it is perfectly straight. If there is
difficulty in making the board li