The solution is forced through five capillary tubes under high pressure, and the filament so obtained solidifying at once is wound together with other similar filaments upon suitable bobbins. Various modifications of this general process are in use, such as the solidification of the solution into threads by passing it into water; the application of solvents less inflammable than ether and alcohol; the use of other forms of dissolved cellulose such as those prepared by means of zinc chloride, ammoniacal copper oxide, or acetic anhydride. In all cases the yarn or thread is submitted to further chemical treatment for the removal of nitric acid and to render the material non-explosive and less inflammable. The finished product is soft and supple, can be easily bleached and dyed, and is capable of acquiring a high lustre. SMOKELESS POWDERS.--(See Explosives.) _Sulpho-Carbonate._--(See Viscose.) SULPHATE CELLULOSE.--Chemical wood pulp prepared by the sulphate process. (See page 107.) SULPHITE CELLULOSE.--Chemical wood pulp prepared by the sulphite process. (See page 107.) VISCOSE.--A soluble sulpho-carbonate of cellulose, prepared by treating cellulose with a 15 per cent. solution of caustic soda, and shaking the product with carbon bisulphide in a closed vessel. The mixture forms a yellowish mass soluble in water, giving a viscous solution which has some remarkable and valuable properties. This _viscose_, on standing, coagulates to a hard mass which can be turned and polished. If spread on glass and coagulated by heat, films are obtained from which the alkaline by-products can be washed out. These films are transparent, colourless, very tough and hard. VULCANISED FIBRE.--Fibre or pulp treated with zinc chloride in acid solution, or otherwise, for the manufacture of hard boards. (See page 139.) WILLESDEN GOODS.--Paper, fibre, and textiles when treated with cuprammonium oxide are partially gelatinised on the surface and rendered waterproof. (See page 139.) _Wood Spirit._--(See Naphtha.) _Xylonite._--(See Celluloid.) FIBRES FOR PAPER-MAKING. Although the vegetable world has been explored from time to time for new supplies of cellulose, and some plants have been found serviceable in certain directions, yet the number of fibres in actual use is very limited. The following table indicates the principal sources of the material required for paper-making:--