THE RAW MATERIAL.-A few remarks at this point upon the nomenclature, countries of produc tion, varieties, characteristics, and mechanical structure, of the raw material of the cotton industry, will obviate the necessity of much repetition in subsequent stages, and enable the reader to compre hend more readily the different points as they come suc,cessively under notice.
The cottons of commerce are generally distinguished by geographical names, borrowed from the countries in which the article is produced. The scientific designations conferred by botanists are unknown in the trade. The prevailing system of nomenclature is unsatisfactory, because it gives rise to arbitrary distinctions ; but custom and experience have obviated most of the practical difficulties, and any attempt to effect a change would probably be quite futile.
The chief contibutors to the European supply are, in the order of their importance, as follows :— The United States, India, Egypt, Brazil, and Peru ; as well as numerous other places of less note. Besides the cottons indigenou,s to most of these countries, nearly all produce different varieties, generally grown from seed of the most popular kinds cultivated in the United States. The following are those usually quoted in the Liverpool Cotton Brokers' Circular ; to them are appended brief descriptions of their important characteristics :— Cotton is valued according to the degree iu which it possesses the special characteristics that best adapt it to the use for which it is intended. As its uses e.re multifarious, the raw material is classified in groups according to the probable wants of different consumers. The qualities chiefly con sidered in classifying cotton are length of staple, fineness, strength, smoothn ess, colour, and cleanliness. Americs,n varieties are classed in four qualities : good ordinary, low middling, middling, and good middling ; South American, three : middling fair, fair, and good fair ; Egyptian, two : fair, and good fair ; East Indian, three : fair, good fair, and good. Standard samples of these classes are preserved for reference, in case of dispute, in the offices of the Liverpool Cotton Brokers' Association ; and it is customary amongst brokers to form a set of the classes in which they deal, and, after careful com parison with the standards, to preserve them for easy reference when required. As, however, the crop of each succeeding year differs in some important respect from its predecessor, these standard samples are subject to considerable modification. According to the relative abundance or scarcity, fulness or deficiency, of special characteristics, the different varieties are classed up or down, as the cases may require. Thus, within a limited range, there is a constant fluctuation of the standard.
The accompanying diagram (Fig. 515) shows the lengths of the staple in several representative varieties : 1 Sea Island, mean length of staple, 1.65 in. ; 2 : Egyptian, 1.50 in. ; 3: Pernambuco, 1-25 in. 4 i American, 1.10 in. ; 5 : Port Natal, 1.10 in. ; 6 : Indian, 0.90 in. ; 7: Indian, 0.65 in.
It will be obvious, from what has already been stated, that considerable skill and discrimination are required in selecting the right qualities of cotton for any required description of yarn, as mis takes cannot be rectified after the cotton has entered the first stage of manufacture.
The mechanical structure of the cotton fibre is such that its perfe,ct 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 three-fourths of the length, when it tapers off to a point. The accompanying illustrations admit of a comparison of the fibres of cotton at different stages of maturity. Fig. 516 exhibits e. portion of mature fibre magnified ; and Fig. 517, sections of the same. The latter show it to be a collapsed cylinder, the walls, as compared with the bore, being of considerable thickness. Fibres possessing these charac teristics are longest and strongeat, and are considered well developed. But amongst the perfect fibre, there is always more or less of unripe, imperfectly developed, or dead, fibre, according to the favourable or unfavourable conditions that have prevailed during the growth of the plant. The proportion of defective fibre naturally present ia always largely increased by the practice, on the part of cotton growers, of collecting the immature pods on the cotton plant, after the latter has been killed by frost, or, from other causes, has ceased to grow. These are dried, and their lint is stripped from them, and added to the bulk. The appeasance presented by the unripe fibre is greatly different, both longitudinally and in section, from that of the mature. In Fig. 518, the half-ripe libre is shown longitudinally ; and in Fig. 519, in section. The least ripe form in which cotton usually appears in commerce is depicted in Figs. 520 and 521. Though twisted almost as much as the perfect fibre, this last is thin, weak, and brittle; and, owing to the de ficiency of cellulose, of which the walla of the mature fibre are composed, it is destitute of the corded edges seen in the latter. In sections, it appears like crooked bits of fine wire, allowing little or no vestige of having been a. hollow cylinder.