SILK, ARTIFICIAL. Artificial silk has been the aim of experimenters for many years. The Comte de Chardonnet, at the Paris Exposition of 1889, exhibited a most ingenious process of producing from cellulose an artificial fibre resembling in all its characteristics and uses the true silk of Bombyx inoni. The cellulose experimented with was principally of cotton and the pulp of soft woods. In making artificial silk from cotton the lint is first carded into wadding, which is im mersed in a mixture of 13 parts of nitric acid of 1.5 specific gravity and 85 parts of commercial sulphuric acid. This process transforms the cot ton into nitro-cellulose and continues until its color, when examined with the microscope and polarized light, is a clear blue. The next stage in the process is to press the nitrated cotton, which is then washed to remove all traces of the acid. It is then dissolved in a mixture of alcohol and ether, forming collodion, which re quires aging in order to secure the best results. This collodion is placed in steel cylinders and the liquid is expelled by pressure through capillary tubes into nitric acid diluted one-half with water. The fibres thus produced are wound di
rectly upon reels and are ready for subsequent treatment. This involves the drying of the fibre by warm air and its denitration in a bath of alkaline sulphide. It then goes through tional washing and drying processes, after which it may be spun and dyed like natural silk. The process with wood fibre is quite similar and there has also been an attempt made to produce a similar fibre by drawing gelatin into fine threads. It is said that the elasticity of ficial silk made by the process described is equal to that of the natural silk, while in lustre and brilliancy it is said to surpass the latter. It was claimed at the time that this silk could be pro duced at from one-third to one-fourth the cost of real silk. Consult Sadtler, Industrial Organic Chemistry. (Philadelphia, 1900). See SILK. Compare natural process described under SILK WORM.