ON BLEACHING, &c.

It is necessary that the binder should be conversant with the best methods for taking out any stains that may, from accident, have been communicated to paper, and also for giving to it a better colour. We shall, therefore, lay down the most simple but approved methods for rendering the material as clear as possible.

There are two ways of whitening paper, viz. by submitting it to the action of vapour, and to that of acids diluted in water. We shall place these, as well as the other receipts, under their proper heads, describing the manipulations peculiar to each method.

ON BLEACHING PAPER GROWN YELLOW BY AGE, &C.

The best proceeding known is the one given by M. Chaptal, and long used by the trade. It is commenced by cutting the bands and separating the sheets, which should be placed in cases formed in a leaden tub, with very thin slips of wood, so that the sheets rest on a plate separated one from the other by intervals scarcely sensible; then pour into the tub oxymuriatic acid or chlorine, taking care that it falls upon the sides so that the leaves are not deranged by the motion. When the workman judges by the whiteness of the paper that it has been sufficiently acted upon, the acid is drawn off by a little cock placed at the bottom of the tub, and its place supplied with fresh clear water several times, to take off, and deprive it of the smell of the acid.