on will stain the paste.

WHITE PASTE FOR MENDING

A good paste for mending is made from a teaspoonful of ordinary flour,
two teaspoonsful of cornflour, half a teaspoonful of alum, and three
ounces of water. These should be carefully mixed, breaking up all
lumps, and then should be heated in a clean saucepan, and stirred all
the time with a wooden or bone spoon. The paste should boil for about
five minutes, but not too fast, or it will burn and turn brown.
Rice-flour or starch may be substituted for cornflour, and for very
white paper the wheaten flour may be omitted. Ordinary paste is not
nearly white enough for mending, and is apt to leave unsightly stains.

Cornflour paste may be used directly after it is made, and will keep
good under ordinary circumstances for about a week. Directly it gets
hard or goes watery, a new batch must be made.

GLUE

It is important for bookbinders that the glue used should be of good
quality, and the best hide glue will be found to answer well. To
prepare it for use, the glue should be broken up into small pieces and
left to soak overnight in water. In the morning it should be soft and
greatly swollen, but not melted, and can then be put in the glue-pot
and gently simmered until it is fluid. It is then ready for use. Glue
loses in quality by being frequently heated, so that it is well not to
make a great quantity at a time. The glue-pot should be thoroughly
cleaned out before new glue is put into it, and the old glue sticking
round the sides taken out.

Glue should be used hot and not too thick. If it is stringy and
difficult to work, it can be broken up by rapidly twisting the brush
in the glue-pot. For paper the glue should be very thin and well
worked up with the brush before using.

The following is quoted from "Chambers' Encyclopaedia" article on
Glue:--

"While England does not excel in the manufacture, it is a recognised
fact that Scottish glue ... ranks in the front of the glues of all
countries. A light-coloured glue is not necessarily good, nor a
dark-coloured glue necessarily bad. A bright, clear, claret colour is
the natural colour of hide glue, which is the best and most
economical.

"Light-coloured glues (as distinguished from gelatine) are made either
from bones or sheepskins. The glue yielded by these materials cannot
compare with the strength of that yielded by hides.

"A great quantity is now made