Simmer the whole for about one hour, then pass through a fine hair sieve or piece of linen. Use this whilst warm.

Simmer and use as above.

Simmer the whole for about one hour, strain as above.

It must be remembered that a size too strong in glue or isinglass is liable to make the paper too brittle; again, some papers require a stronger size than others.

(4). A size that may be used cold, and is recommended in France, to keep at hand and to use when only a single leaf requires sizing, such as when a name has been erased from a title-page, is as follows:—Boil about a quart of water in a saucepan. Whilst boiling, add about two oz. of shellac and 1 ⁄ 2 oz. of borax; the borax will dissolve the shellac, which will be held in suspension; the whole must then be passed through a fine hair sieve, or piece of linen, to rid it of all pieces or impurities. This will keep a very long time, and may be used over and over again.

Great care must be exercised that not too much shellac is used, or the paper will be rendered transparent. |161|

MANIPULATION.

Dust.—The careful application of india-rubber or bread will generally take away all dust. In using india-rubber, hold the sheet or leaf down by the left hand, and rub gently away from it. If the rubber is used in a to and fro motion, there is great danger of the sheet doubling back and breaking. The bread may be used in a circular motion; and if a book be cleaned from dust by this means without pulling to pieces, all crumbs must be brushed away from the back very carefully before closing the book.