Besides these, which are well-known trade definitions, there are very many others, amounting, if we include paste and mill boards, to at least 12 or 15 hundred, so that even paper-manufacturers require the aid of a treatise upon the subject of the sizes, qualities, etc., and such a treatise is in common use.
Even as regards materials, varieties are endless. In an old German book by Jacob Christian Schilffers, published at Regensburg in 1772, there are no less than 81 samples of different kinds of paper bound up and forming part of the book, and innumerable others have been made since.
Rice paper is a beautiful material imported from China, about which numberless errors have been written. It is now known to be formed of thin slices of the pith of the plant called aralia pap'rifera. This pith can be obtained from the stems in beautiful cylinders, from 1 to 2 in. in diameter, and several inches in length. The Chinese work men apply the blade of a sharp, straight knife to these cylinders of pith, and, turning them round dexterously, pare them from the circumference to the center, making a rolled layer of equal thickness throughout, This is unrolled, and weights are placed upon it until it is rendered perfectly smooth and fiat. Sometimes a number are joined together to increase the size of the sheets. It ivill be seen that this more nearly resem bles the ancient papyrus than modern paper; but. it is more beautiful than the former, being a very pure pearly white,- and admirably adapted to the peculiar style of painting of the Chinese. 1• The ordinary papers of the Chinese, Japanese, and East Indians have much resem blance to each other, which arises from the manufacture and material being similar; the bark of the paper mulberry (hroussonetia papyrifera) being chiefly used. The Chinese
and Japanese are the most skillful paper-makers in the world, and some of the East Indian papers surpass the European manufactures completely.
Some useful kinds of paper are the result of manipulations subsequent to the paper maker's work. Thus: Lithographic Paper is prepared from good printing-paper by laying on one side of the sheets a preparation consisting of. six parts of starch,1 of alum, and 2 of gum-arabic dissolved in warm water, and applied whilst hot with a proper brush.* Generally a little gamboge is added, to give it a slight yellow color.
Copying Paper, for manifold writers, is made by applying :a composition of lard and black-lead to one side or both of sheets of writing-paper; and after leaving it on for a day or so, it is carefully and smoothly scraped wiped with a soft cloth.
Tracing Paper is good printing-paper rendered transparent by brushing it over with a mixture of Canada balsam and oil of turpentine, or nut oil and turpentine. In either case it must be carefully dried before using.
There are two distinct classes of colored papers. In one, the color is introduced into the pulp, and is consequently in the body of the paper; in the other, the colors are mixed with size, and applied to the surface. There have been many ingenious and tasteful inventions for decorating the surface of paper, such as by.giving it a marbled and even a beautiful iridescent appearance, but they are too numerous for the limits of this article.
Paper is subject to much adulteration. China-clay and gypsum are generally used for the white sorts, and the heavy ferruginous others for the coarse and brown kinds.