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tion—we incline to believe the former, the effect being that a vacuum is formed in the hollow of the fibre. This absorption of the fluid is not instantaneous, but extends probably over several, say two or three, days. The apex extremity of the fibre is a cone of what may be called almost solid cellulose, which nearer the base gradually opens into the tubular form, which is continued to the junction of the fibre with the seed. As the circulatory fluids are withdrawn, the vacuum is formed in the tube at the point nearest to the extremity of the fibre, and at which it begins to collapse owing to the pressure of the atmosphere, the process closely following the retreating fluid down the length of the cylinder to its base in the seed. The consequence is that the free end of the fibre is twisted on its own axis a considerable number of times, and as this is going on simultaneously in almost every fibre of one pod, the primary order of arrangement is disturbed to such an extent that the carpel is burst open and the mass of fibres is exposed to the dessicating influence of the sun's rays, which quickly completes the process. The form of the fibre has now been changed from the hollow cylinder maintained during growth to that with which we are most familiar, a twisted ribbon-like figure having corded edges. This corded form of the edges is caused simply by the bending of the fibre walls upon themselves in the action of collapsing and is a necessity of a properly developed fibre. Such the writer believes is the normal process of development in the cotton fibre, which results in a mechanical configuration that admirably fits it for the purpose which nature designed, namely, the dispersion of the seed, and also for the use to which it has been converted by man.

Against this theory it may be urged that in all pods of cotton short, immature, or undeveloped fibres are always to be found. In reply to this it will be sufficient to point out that growth does not commence in all the fibres of one pod, or indeed of one seed, simultaneously; hence all do not reach maturity at the same moment; neither are all

the germinal cells of the fibres equally vigorous in secretive or circulative power: hence both length and diameter of fibres may differ considerably. Neither does the safety nor natural propagation of the seed require that all the fibres of each seed should be perfectly developed; it is sufficient for natural requirements if they form a loose flossy mass presenting a great surface with little weight to the action of the winds, which, if not interfered with, would carry them far and wide in the locality of their growth. In some instances very thin transparent and flat fibres are present: possibly owing to the reproductive power of the cells operating in all their force whilst the circulation of the vital fluid is weak, impeded, or entirely obstructed. These undeveloped walls may collapse without producing a single convolution of the fibre; hence the ribbon-like, transparent, and apparently structureless character of these fibres.

The mechanical structure of the cotton fibre, as the writer has observed in another place, is such that its perfect development has an important bearing upon its quality. As received in this country mature or ripe cotton fibres when placed under the microscope present the appearance of irregularly twisted ribbons with thick rounded edges. The thickest part is the root end, or base, that which was attached to the seed. The diameter of the cylinder remains without material change through, probably, threefourths of its length, after which it more rapidly tapers to a point. The accompanying illustrations admit of a comparison of the fibres of cotton at different stages of growth or development. Figs. 11 and 14 exhibit a portion of mature fibre and sections magnified. The latter show it to be a collapsed cylinder, the walls as compared with the bore being of considerable thickness. The one or two exceptions to this form are probably instances in which the cylindrical form has been ruptured. Fibres possessing these characteristics are considered well developed, being the longest and strongest. But amongst the perfect fibre there is always

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more or less of unripe, imperfectly developed, or dead fibre, this being less or more accordingly as the surroundings have been favourable or unfavourable during the period of

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Fig. 11.

Fig. 12.

Fig. 13. Fig. 14. Fig. 15. Fig. 16. growth. In commercial cottons, especially of the lower grades, the proportion of defective fibre is always largely increased by the practice common, if not general, amongst cotton growers of collecting the immature pods on the cotton

plant after the latter has been killed by frost, or from exhaustion of their vital power have ceased to grow. These are dried and the lint stripped from them, which is added to the bulk. The appearance of the unripe fibre is very different, both longitudinally and in section, from that which is mature. In Figs. 12 and 15 the half ripe fibre is shown longitudinally and in section. In this case the ribbon is and the thickness of the The sections show the col

flatter, the twists are fewer, corded edges is diminished. lapse of the tube to be so complete as almost to destroy all trace of the original cylindrical form. The least ripe fibres that appear in commercial cottons are illustrated in Figs. 13 and 16. The twisting is further diminished, and the corded edge disappears altogether. The internal surfaces adhere so closely that the hollow is quite lost, and the sections appear like crooked bits of fine wire. This is owing to the deficient quantity of the cellulose deposited. These fibres are thin, brittle and weak, and incapable of taking dye-stuffs in dyeing and printing.

Occasionally these defective fibres are found in greater abundance than at other times, and more frequently in irregularly grown cottons, or the cottons of those countries where the plant is apt to suffer from a deficiency of moisture, as in Indian cottons. When abundantly present they greatly depreciate the working qualities of the bulk, and it is an important matter in judging of cotton to be able to distinguish them. This ability may be acquired by careful observation, and in this the natural sight may be beneficially aided by a powerful lens.

The mechanical structure of cotton fibres, especially in having a convolute form and corded edges, peculiarly adapt them for numerous uses. If they were cylindrical like the fibres of flax and hemp, they would be too short to hold together when spun into a thread. When the proper structure is fully developed, in the twisting process they become firmly bound together, one fibre folding over and gripping the corded edge of another, thereby enabling a con

tinuous thread of considerable strength to be made. When the finest and longest stapled varieties of cotton are used, this thread is capable of great attenuation. Cotton gathered from the unopened pod does not possess the perfect convolute form in the fibre; and, as seen in the illustrations, fibres that from other causes are imperfectly developed come in the same category: hence do not possess the same cohesive power when spun into yarn. When present to any appreciable extent they are the cause of serious defects when the yarn or cloth containing them has to be dyed or printed. The convolutions in Egyptian and American cottons are more regular and the development more perfect than in other descriptions, which fully accounts for the acknowledged superiority of these varieties. The naked eye is incapable of distinguishing these twistings, but the microscope shows them to amount to from one hundred to three hundred an inch, and closer investigation would probably show a wider variation than even this.

It will interest the reader to have placed before him the results of some very recent researches into the structure of the cotton fibre. These have been conducted by Mr. John Butterworth of Shaw, and were first made public in a paper read before the Oldham Microscopical Society, on April 10th in the current year (1883), and communicated to the present writer for publication in the "Textile Manufacturer." In the year 1863 Mr. Charles O'Neil of Manchester, well known as a writer on tinctorial matters, had been conducting some researches in connection with the cotton fibre and its behaviour under certain chemical agents. In employing Schweitzer's solution (an ammoniacal solution of oxide of copper) for dissolving cotton and other forms of cellulose, he made numerous experiments upon the former, watching its action upon the fibre by means of the microscope. In the course of these he thought he could discern four distinct parts of the fibre-1st, the outside membrane, which did not dissolve in the solution; 2nd, the real cellulose beneath, which dissolved, first swel

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