Natural - (1) In making natural parchment, the pelts, after liming, washing, and fleshing, as for leather-dressing, are split by the splitting-machine, and the inner layer is taken for making parchment. Knots are made in the edges of this layer by tying up portions of lime or rubbish into balls all round, and by these knots the skin is stretched upon wooden frames. Whilst on the frames, the split side is scraped to render it even, and the skin is then "dubbed" with whiting and a strong solution of soda-ash to get out the grease. Next it undergoes a series of scaldings with hot water thrown upon it out of a bowl, of scrapings, and of washings with whiting and water, and is finally dried in a warm chamber. (Ballard.)
(2) To make parchment transparent, soak a thin skin of it in a strong lye of wood-ashes, often wringing it out till it becomes transparent; then strain it on a frame and let it dry. This will be much improved if, after it is dry, it receives a coat on both sides of clear mastic varnish, diluted with spirits of turpentine.
(1) Strong unsized paper is immersed for a few seconds in oil of vitriol (concentrated commercial sulphuric acid), diluted with half its volume of water. It is then washed in pure water or weak ammonia water. It strongly resembles animal parchment, and is used for the same purposes. The acid solution must be exactly of the strength indicated, and not warmer than the surrounding atmosphere.
(2) Another method consists in using the commercial oil of vitriol in an undiluted state. The paper is first passed through a solution of alum and thoroughly dried previous to its immersion, thus preventing any undue action of the corrosive principle of the vitriol. After the application of the acid, the paper is passed into a vat of water, and then through an alkaline bath, to be again washed. Written and printed paper may undergo this process without materially affecting the clearness and distinctness of the letters, and the paper retains all its qualities, even after being wetted several times in succession; while paper prepared in the usual manner loses, to a great extent, its pliancy, and becomes hard and stiff.
(3) By immersing cellulose for a few seconds in a perfectly cold mixture of 2 parts oil of vitriol and 1 of water, although no alteration of its chemical constituents takes place - except perhaps a purely molecular one - its physical characteristics are greatly changed, it being converted into a leather-like body of great comparative toughness. White unsized paper - itself a tolerably pure form of cellulose - thus treated, goes by the name of "parchment paper," and its tensile strength is increased to some 40 or 45 times that of the original paper used. This form of cellulose is especially well adapted for many purposes in medicine and pharmacy, including " caps" for jars and bottles, sample envelopes, labels, " untearable tallies," and even certain forms of surgical bandages. By treating "parchment" or " Gaine's " paper - as it is sometimes called from the name of its inventor - with a little hot strong solution of gelatine, to which about 2£ or 3 per cent, of glycerine has been added, and allowing it to dry, it may be rendered tolerably impervious to fatty matters, so that it then forms a convenient medium in which to pack small quantities of such substances as ordinarily are apt to soil the paper they are wrapped in.
The same altered variety of cellulose, if soaked with benzol or carbon bisulphide holding 1 per cent, of linseed-oil and 4 of indiarubber in solution, makes, when dry, an admirable and inexpensive waterproof envelope for the preservation and transport of drugs and deliquescent salts. By using an envelope of this description, closing it carefully (when filled) with a little stronger solution of caoutchouc, and afterwards placing the same inside a similar one of large size containing fine oven-dried oatmeal, even calcium chloride and crystals of ammonium nitrate have been forwarded in damp weather without their having attracted moisture or suffered any appreciable change during transit. (Monthl. Mag.) Removing wrinkles. - When parchment documents are wrinkled and creased, the evil may be remedied, without injury to the writing, in the following manner; - Place the document, face downward, upon a clean piece of blotting-paper. Beat up to a clear froth, with a few drops of clove-oil, the whites of several fresh eggs, and with the fingers spread this over the back of the sheet, and rub it in until the parchment becomes uniformly soft and yielding.
Then spread it out as smoothly as possible, cover it with a piece of oiled silk, put on it a piece of smooth board, and set it aside in a cool place, with a weight on the board, for 24 hours. Then remove the board and silk, cover with a piece of fine linen cloth, and press with a hot smoothing-iron (not too hot) until all signs of wrinkles have disappeared. The heat renders the albumen insoluble, and not liable to change.