COTTON.

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experiments of Mr. Walter Crum. These so-called dead fibres whenexamined with a microscope were found to be of such very thin texture as tobe almost invisible except at the edges; they are nearly twice as wide asordinary ripe cotton, and contain a larger number of longitudinal and transversefolds. This dead cotton is not equally conspicuous with all dyes; it is veryapparent with indigo and madder-pink, but not so with safflower and deepmadder-red.

For the benefit of those to whom the “ Memoirs of the Literary andPhilosophical Society of Manchester ” may not be conveniently accessible, weabridge from the fourth volume of the third series some of the interesting andhighly valuable researches of Dr. Schunck, F.R.S., “On some Constituents ofthe Cotton Fibre.”

Dr. Schunck’s endeavour was to throw a little more light on the nature ofthe substances which are contained in or attached to the framework ofcellulose of which cotton fibre mainly consists, and which are, together withthe latter, produced by the plant, without taking into consideration the foreignand extraneous matters introduced during the process of manufacture. It iswell known that these substances are almost insoluble in water, but solublein hot alkaline lye. Indeed the principal operation in the bleaching of cottongoods consists in subjecting them for some time to the action of boilingsolutions of soda or some other alkali—chlorine or its compounds being onlyused to impart to them the highest degree of whiteness. Dr. Schunck con-fined himself in this investigation to those natural constituents of cottonfibre which are insoluble in water, but soluble in alkaline lye, and which areafterwards precipitated from the alkaline solution by acid. He employedcotton-yarn made from definite unmixed kinds of cotton. Apart fromfinancial considerations, yarn presents certain advantages as compared withraw cotton. It is much freer from mechanical impurities, which are to a greatextent removed during, or rather previously to, the operations of spinning;while, on the other hand, in a well-ordered manufactory, little or nothingof a foreign nature is added to the cotton to render it impure. It can also" betreated without any trouble, and in large quantities, in the ordinary vessels-used by bleachers, without rendering it necessary to set up special apparatusfor the purpose.

In the first experiment, 450 lbs. of No. 20 yarn, carefully spun from EastIndian cotton, of the variety called “ Dhollerah,” was treated, in an ordinarybleacher’s kier heated by steam, with boiling water containing 13! lbs. of soda-ash for seven and a half hours. The resulting dark brown liquor, after theyarn had been taken out, drained, and slightly washed, was removed intoanother vessel and mixed with an excess of sulphuric acid, which produced acopious, light brown, flocculent precipitate, while the liquid became nearlycolourless. This precipitate was allowed to settle ; the liquid was poured off,,and, after being washed with cold water to remove the sulphate of soda andexcess of acid, the precipitate was put on strainers of calico and allowed todrain—an operation which, in consequence of its gelatinous nature, occupiedsome time. A thick pulp was thus obtained, which was found to weigh 60 lbs.Of this 3 lbs. was taken and dried completely, at first in a stove and then in awater-bath, when it left 531 grs. of a brown, brittle, horn-like substance,translucent at the edges. The whole of the precipitate, if dried, would there-fore have weighed 10,620 grs., which is equal to 0*337 per cent of the weight