Linen, a well known kind of cloth, made chiefly of Hemp and Flax.- Having already described the different processes which these substances undergo, before they are converted into cloth, we shall at present add only such facts, as may tend to render our former statement more satisfactory.—After the filaments have been properly dressed and combed (see vol. ii. p. 302), the flax is spun into the yarn by the hand, in the usual manner: instead, however, of moistening the threads with spittle, or common water, we would recommend the mucilage prepared from the Common Comfrey (which see) to be preferably employed. By such simple means, the saliva, so useful in the process of digestion, may not only be saved, but the yarn will be totally divested of its brittleness-, and, in other respects, considerably improved. Next, the yarn is conveyed to the loom, where it is woven into cloth (a process similar to that practised with wool, and described under the article Cloth, vol. ii.) ; after which it is bleached, in the manner stated under that head, in our first volume.
Linen is more difficult to be dyed of a black colour, than either wool or cotton. The black, imparted to it by means of green vitriol and galls, soon disappears by washing. It is, therefore, a desideratum of considerable import-ance, to procure such a preparation as will strike a beautiful, deep, and permanent black: for this purpose, we subjoin the following account, by M. Vogler, of Weil-burg. One quart of pure, soft water, is to be mixed in a large bottle, with two ounces, or two ounces and a half of common aquafortis ; to which a similar quantity of litharge should be gradually added: the bottle, after being slightly corked, must be kept in a warm place, and occasionally shaken. In the course of a few days, the liquid may be poured iuto a deep earthen, leaden, or pewter vessel; when the linen intended to be dyed, should be well washed (though not bleached), and immersed in it for ten or twelve hours. It is then to be taken out, and, after being washed and rinsed three times in pure cold water, it ought to be dipped in a weak solution of common glue ; again rinsed, and then placed in the shade to dry.
Three quarters of an ounce of galls, well bruise 1, are now to be boiled in a quart of rain, or other pure, soft water, for eight or ten minutes, when a similar quantity of common salt is to be added; and, as soon as the latter is dissolved, the linen should be boiled in the liquor for seven or eight minutes ; then taken out, washed, wrung three times as before, and dried in the shade. By these operations, the stuff will imbibe a dark grey-yellowish tinge, that disposes it for the better reception of the colour.
Three quarters of an ounce of copperas, or vitriol of iron, and a similar quantity of common salt, are now to be dissolved in a quart of pure, hot water, and the linen immersed in the liquid for eight or ten hours; when it must again be
LlN washed, rinsed, and suspended for drying in the shade.
In order to strike the black co-lour, M. Vogler next directs three quarters of an ounce of logwood to be boiled for seven or eight minutes, in somewhat more than two quarts of rain or river water, when a quarter of an ounce of white starch should be added, having previously been mixed with a small quantity of fresh water, to prevent the rising of lumps. As soon as this is perfectly dissolved, the stuff ought to be boiled in the liquor for seven or eight minutes, after which it must undergo the same treatment as has been repeatedly specified.
The linen will thus acquire a fine black tinge ; but, if the dye be not sufficiently deep, it may again be immersed in the decoction of logwood, and treated in the manner above stated, till the requisite shade be obtained. But as the stuff, in this state, will not admit of being washed in ley, or soap-water, without losing its colour, M. Vogler farther directs it to be dipped in a cold solution, prepared by boiling an ounce of galls, well bruised, for seven or eight minutes, in a quart of the glue-water, in which an ounce of copperas should then be dissolved. After the linen has remained one hour in this liquor, it must be pressed and dried in the shade: in conse quence of these processes, it will acquire a beautiful and permanent black colour.
A durable, but expensive, purple dye may be communicated to linen, by immersing it in a solution of gold, in aqua-regia.—For this purpose, the latter ought to be fully saturated with the metal, and be diluted with a triple quantity of water; if a deep colour be re quired, the piece, when dry, must be repeatedly steeped in it; and as the tinge frequently does not appear for several days, the stuff should be exposed to the sun or free air, and be occasionally removed to a damp place, or moistened with water.
Various patents have been granted for different processes relative to the bleaching, etc. of linen, cloths. Several of these have already been noticed under the articles Bleaching, Cloth, etc. : we shall, therefore, mention only. a few others, to render our account more complete.
Among these are, 1. Mr. Ten-nant's, in 1799, for preparing the oxygenated muriates of calcareous earths, etc ; in a dry form, and applying them to bleaching, etc. 2. Mr. Gillespie's, in the same year, for a new mode of printing linens, etc. ; 3. Mr. Foden's, in 1800, for a crystalline size, for dressing linen, etc. The reader will find an account of these in the later volumes of the Repertory of Arts, etc. where diffuse specifications are inserted.
As various frauds are often committed by unprincipled persons, who erase the marks, or initials, made on linen with silk, we.think it will be useful to communicate the following recipe, which was recommended by the late Dr. Smellie - he directs about half an ounce of vermilion, and two drams of the salt of steel, to be finely levigated with linseed-oil; the thickness or limpidity of which may be varied as occasion may require. This preparation for marking linen is stated to be equal, if not superior, to the various compositions vended in the shops; and it perfectly resists the effects both of acids, and of alkaline leys.
Lastly, we cannot conclude this article, without recommending the strictest care to be taken in avoid-ing the use of damp linen, in any, form whatever; as we are convinced that many, by. neglecting' this simple precaution, have met with a premature dissolution. And, if some regulations were made re-. specting. inn-keepers, as far as re-lates to this subject, catarrhs, and various other diseases, would fre-qucntly be prevented.