independent of the true fibrous substance, but it is well to recognize that if the wool-fibre be entirely freed from the wool-fat it loses its plastic and elastic nature and is considerably damaged. In cleansing wool the true fibre mass may be disturbed and partially destroyed not only by dry but also by “wet” heat, and may be entirely disintegrated by means of alkalies, &c., with heat. The wool-fibre will almost free itself from the natural impurities—the yolk—in the presence of tepid water. This is taken advantage of in the various steeping machines placed on the market, which partially scour the wool by means of its own yolk—principally through the potash salts present.
According to Hummel the composition of the average wool-yolk is as follows:-
|
|
The potash salts are usually recovered from the wash-water products and a marked economy thereby effected.
The natural wool-fat—popularly known as “lanoline”—may be partially got rid of in the steeping process, but it is almost invariably necessary to free the wool still further from it by actually scouring the wool on either the “emulsion” or “solvent” method, in either case the action being largely physical. As previously pointed out, however, all the wool-fat must not be taken away from the fibre, or the fibre will lose its “nature.” According to Dr Bowman, the chemical composition of the cell structure of the average wool-fibre is:—
|
| ||||||||||
|
It is said to be a most complex body of which the probable formula is C42H157N5SO15.
If wool is burnt, it largely resolves itself into ammonia gas—whence it derives its characteristic odour—and carbon “beads” or “remains,” which serve to distinguish wool from cotton, which, upon being burnt, does not smoulder but burns with a flash and leaves no beads. For further particulars on the organic nature of the wool fibre see Fibres.
The bulk of the wool of commerce comes into the market in the form of fleece wool, the product of a single year's growth, cut from Lamb, Hogg and Wether wool. the body of the living animal. The first and finest clip, called lambs' wool, may be taken from the young sheep at the age of eight months. When the animal is not shorn till it attains the age of twelve or fourteen months the wool is known as hogg or hogget, and, like lambs' wool, is fine and tapers to a point. All subsequently cut fleeces are known as wether wool, and possess relatively somewhat less value than the first clip. Fleece wool as it comes into the market is “in the grease,” that is, unwashed, and with all the dirt which gathers to the surface of the greasy wool present; or it is received as “washed” wool, the washing being done as a preliminary to the sheep-shearing, or, in some few cases, it is scoured and is consequently stated as “scoured.” Skin wool is that which is obtained from sheep which either die or are killed. Typical skin wool is that which has been removed by a sweating process. The worst type of skin wool—technically known as “slipe”—is removed from the skins by lime, which naturally affects the handle of the wool and renders it difficult to bring into a workable condition later. Mazamet in France is the great continental centre for skin wools.
Where there is abundance of water and other conveniences it is the practice to wash or half-wash sheep previous to shearing, and Sheep washing. such wool comes into the market as washed or half-washed fleece. The surface of a fleece has usually a thick coating of dirt, and in the case of merino breeds the fleece surface is firmly caked together into solid masses, from the adhesion of dirt to the wool constantly moist with the exudation from the skin of the greasy yolk or “suint,” so that in an unwashed very greasy fleece 30% of weight may represent dirt, and about 40% the greasy suint which lubricates the wool, while the pure wool is not more than one-third part of the whole. Where running streams exist, the sheep are penned by the side of the water, and taken one by one and held in the stream while they are washed, one man holding and the other washing. The operation is objectionable in many ways, as it pollutes the stream, and it dissipates no mean amount of potash salts, valuable for manure or for other chemical purposes. Sheep washing appliances are now largely employed, the arrangement consisting of a pen into which the sheep are driven and subjected to a strong spray of water either hot or cold, which soaks the fleece and softens the dirt. This done, they are caused to swim along a tank which narrows towards the exit, and just as they pass out of the pen they are caught and subjected to a strong douche of pure water. They should then be kept on grass land free from straw, sand, &c., so that the wool may be sheared free from vegetable matter, &c. After a few days the wool of a washed sheep is sufficiently dry for shearing or clipping.
The relative advantages of shipping wool in the greasy or washed state have been fiercely debated. Although there are naturally exceptions, the superiority of greasy wool is now generally recognized. This is not only because the wool more fully retains its nature, but because it is more readily judged for “yield” and its spinning qualities are, perhaps, more readily estimated.
The following list gives an idea of the yield in clean wool of the chief commercial varieties, from which it will be noted that roughly merino greasy wool yields about 50% clean wool and English about 75% clean wool.
| Type of Wool. |
Yield per cent of Clean Wool. | |||||||||||||||||||||
|
|
A skilful shearer will clip the fleece from a sheep in one unbroken continuous sheet, retaining the form and relative positions of the Sheep shearing. mass almost as if the creature had been skinned. In this unbroken condition each fleece is rolled up by itself and tied with its own wool, which greatly facilitates the sorting or stapling which all wool undergoes for the separation of the several qualities which make up the fleece. Mechanical shears have almost revolutionized the shearing industry, a good shearer shearing from 100 to 200 sheep per day.
On the great Australian sheep stations wool classing is one of the most important operations, largely taking the place of sorting in the Wool classing. English wool trade. This is no doubt due to the wonderful success which has attended the efforts of the Australian sheep breeders to breed a sheep of uniform staple throughout. Thus the fleeces as taken from the sheep are skirted and trimmed on one table and then passed on to the classer, who places them in the 56's, 60's, 64's, 70's, 80's or 90's class according to their fineness, these numbers approximately indicating the worsted counts to which it is supposed they will spin. The shorter Australian wools not coming under any of these heads are classed as super-clothing, ordinary clothing, &c., being more suitable for the woollen industry.
The art of sheep shearing, skirting, classing, packing and transporting has been brought up to a wonderful state of perfection in Australia, and the “get up” of the wool is usually much superior to the “get up” of the “home-clip.” Of late there has been an outcry against the prevalence of vegetable matter in colonial wools, but it seems probable that with the adoption of a suitable woolpack, and the exercising of a little more care in sorting at the home end, this difficulty will be satisfactorily surmounted.
Sorting or stapling was formerly a distinct industry, and to some extent it is so still, though frequently the work is done on the Wool sorting. premises of the comber or spinner. Carding wools are separated and classed differently from combing wools, and in dealing with fleeces from different breeds, the classification of the sorter varies. In the woollen trade short-staple wool is separated into qualities, known, in descending series from the finest to the most worthless, as picklock, prime, choice, super, head, seconds, abb and breech, and the proportions in which the higher and lower qualities are present are determined by the “class” of the fleece. In the worsted trade the classification goes, also in descending series, from fine, blue, neat, brown, breech, downright, seconds, to abb for English wools. The last three are short and not commonly used in the worsted trade. The greater proportion of good English long wool will be classified as blue, neat and brown; it is only in exceptional cases that more than from 5 to 8% is “fine” on the one hand, or of lower quality than breech on the other. Generally speaking, the best portion of a fleece is from the shoulders and side of the animal. The quality decreases towards the tail end of the sheep, the “britch” being frequently long, strong and irregular. The belly wool is short, worn and dirty, as is also the front of the throat, while on tie head and shins the product is short, stiff and straight, more like hair than wool and is liable to contain grey hairs. The colonial wools come “classed,” and consequently are only as a rule sorted into three or four qualities. Thus a 60's fleece may be sorted into 56's, ordinary 60's, super 60's and skirting's.
The sorter works at a table or frame covered with wire netting through which dust and dirt fall as he handles the wool. Fleeces which have been hard packed in bales, especially if unwashed, go into dense hard masses, which may be heated till the softening of the yolk and the swelling of the fibres make them pliable and easily opened up. When the fleece is spread out the stapler first divides it into two equal sides; then he picks away all straws, large burrs, and tarry fragments which are visible; and then with marvellous precision and certainty he picks out his separate qualities, throwing each lot into
