4. A square inch of the fabric or a small portion of the yarn, is boiled for a short time in a solution of caustic soda or potassa, and then withdrawn and washed. If it be of pure wool, it will be dissolved, and wholly disappear; if any threads or fibres are left undissolved, they consist of either cotton or linen; of these, such as have acquired a dark yellow tinge, are linen, whilst those which have retained their whiteness, or which are only slightly discoloured, are cotton. The relative proportion of the adulteration may be ascertained as before. See Cotton, Linen, and Silk.
Wool and woollen goods exhibit a greater affinity for colouring matter than either cotton or linen, and in many cases this exceeds even that of silk. The most difficult dye to impart to wool is a rich, deep, and permanent black. See Dyeing, Mordants, &c.
Woollen goods are cleaned and scoured in the manner noticed under Bleaching and Scouring.
Wool, Spanish. Rouge-crepons.
Wool, Styptic. Dr. Erie, of Isny, prepares this by boiling the finest carded wool for half an hour or an hour in a solution containing 4 per cent. of soda, then thoroughly washes it out in cold spring water, wrings it; and dries it. The wool is thus effectually purified, and is now capable of imbibing fluids
uniformly. It is then to be dipped two or three times in fluid chloride of iron diluted with one-third of water, expressed and dried in a draught of air, but not in the sun or by the aid of high heat; finally, it is carded out. Thus prepared, it is of a beautiful yellowish-brown colour, and feels like ordinary dry cotton wool.
As it is highly hygroscopic, it must be kept dry, and when required to be transported, must be packed in caoutchouc or bladder. Charpie may be prepared in a similar manner, but on account of its coarser texture, is not so effective as cotton wool, presenting a less surface for producing coagulation. When the wool is placed on a bleeding wound, it induces moderate contraction of the tissue, coagulation of the blood that has escaped, and subsequently coagulation of the blood that is contained within the injured vessels, and thus arrests the hæmorrhage. The coagulating power of the chloride of iron is clearly exalted by the extension of its surface that is in this way affected. The application of the prepared wool is not particularly painful, whilst by sucking up the superfluous discharge, and preventing its decomposition, it seems to operate favorably on the process of the wound.[272]
[272] ‘Lancet.’
Wool Work, Woollen Shawls, &c., to clean.—Boil a large piece of soap in rain-water. Put it into an earthenware pan and add a teacupful of ox-gall, which any butcher will supply. Put in the work to be cleaned, and rub it briskly, as you would a pocket handkerchief, lifting it up and down. Wash in two waters, if very dirty; then rinse quickly in cold water, lay a cloth over it, and fold it tightly. Iron it immediately on the wrong side with hot, heavy irons.
WOORA′RA. Syn. Ourari, Wourali. A deadly poison employed in Guiana, obtained from the Strychnos toxifera. See Upas.