PARCHMENT. This writing material has been known since the earliest times, but is now made in a very superior man ner to what it was anciently. The art of making parchment consists in certain manipulations necessary to prepare the skins of animals of such thinness, flex ibility and firmness, as may be required for the different uses to which this sub stance is applied. Though the skins of all animals might be converted into writing materials, only those of the sheep or the she-goat are used for parchment ; those of calves, kids, and dead-born lambs for vellum ; those of the he-goat, she-goat, and wolves for drum-heads and those of the ass for battle-doors. All these skins are prepared in the same way, with slight variations.
They are first of all prepared by the leathertdresser. After they are taken out of the lime-pit, shaved, and well washed, they must be set to dry in such a way as to prevent their puckering, and to render them easily worked. The small manu facturers make use of hoops for this pur pose, but the greater employ a herse, or stout wooden frame. This is formed of two uprights and two cross-bars solidly joined together by tenons and mortises, so as to form a strong piece of carpentry, which is to be fixed up against a wall. These four bars are perforated all over with a series of holes, of such dimensions as to receive slightly tapered, box-wood pins, truly turned, or even iron bolts.
Each of these pins is transpierced with a hole like the pin of a violin, by means of which the strings employed in stretch ing the skin may be tightened. Above the herse a shelf is placed for receiving the tools which the workman needs to have always at hand. In order to stretch the skin upon the frame, larger or smaller skewers are employed, according as a greater or smaller piece of it is to be laid hold of. Six holes are made in a straight line to receive the larger, and four to receive the smaller skewers or pins. These small slits are made with a tool like a carpen ter's chisel, and of the exact size to admit the skewer. The string round the skewer is affixed to one of the bolts in the frame, which are turned round by means of a key, like that by which pianos and harps are tuned. The skewer is threaded
through the skin in a state of tension.
Every thing being thus prepared, and the skin being well softened, the work man stretches it powerfully by means of the skewers ; he attaches the cords to the skewers, and fixes their ends to the iron pegs or pins. He then stretches the skin, first with his hand applied to the pins, and afterwards with the key. Great care must be taken that no wrinkles are formed. The skin is usually stretched more in length than in breadth, from the custom of the trade ; though extension in breadth would be preferable, in order to reduce the thickness of the part opposite the backbone.
The workman now takes the fleshing tool represented under CCIuIYINO. It is a semicircular double-edged knife, made fast into a double wooden handle. The workman seizes the tool in his two hands, so as to place the edge perpendicularly to the skin, and pressing it carefully from above downwards, removes the fleshy excrescences, and lays them aside for making glue. He now turns round the herse upon the wall, in order to get access to the outside of the skin, and to serape it with the tool inverted, so as to run no risk of cutting the epidermis. He thus removes any adhering filth, and squeezes out some water. The skin must next be ground. For this purpose it is sprinkled upon the fleshy side with sifted chalk or slaked lime, and then rubbed in all directions with a piece of pumice stone, 4 to 5 inches in area, previously flattened upon a sandstone. The lime gets soon moist from the water contained In the skin. The pumice-stone is then rubbed over the other side of the skin, but without chalk or limo. This opera tiots is necessary only for the best parch ment or vellum. The skin is now allow ed to dry upon the frame ; being care fully protected from sunshine, and from frost. It is afterwards scraped, rubbed, and polished with pumice. It is occa sionally colored green with a mixture of cream of tartar, verdigris, and nitric acid, and finally receives a gloss from the white of egg or mucilage, laid on with a brush.