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warp which pass through the same interval in the reed, will appear close together in the cloth with a vacancy between them, and those next to them ; which vacancy is caused by the intervention of the dents in the reed. But if the yarn beam is raised considerably above the level of the headles, the warp when at rest, will no longer be in a straight line; and when the shed is opened, that half of the warp which descends, will be drawn considerably tighter than the half which rises. Thus each half will be slackened alternately, and the consequence of this is, that the warp spreads in the cloth, and the intervals caused by the dent of the reed are no longer discernalle.
The former of these ways of placing the loom is practised in thin work, the latter in thick.
When the west has been thrown across the warp, if the fabric is thin, the lay is brought up rather before the shed is closed, in order that the west may be struck up as tight or as stretched as possible ; but in weaving thick goods, the shed is closed before the stroke of the lay is given.
In consequence of this, the threads of the warp, to a certain degree, slacken the weft, and give a close appearance to the cloth.
In weaving thick cotton goods, the weft is inserted in a wet state, when the fabric is wanted to appear very close.
It may now be proper to notice the defects which most commonly occur in the weaving of cloth, and to explain the causes from which they arise.
When from any cause, the west is not regularly interwoven with the warp, a deficiency must happen in the cloth, which is called by weavers a scobb or blotch.
This may proceed from several causes, the most frequent is some obstruction in the warp, which prevents any portion of it from rising or sinking regularly when the shed is formed ; of course, the shuttle, instead of passing fairly between the threads of the warp, passes either over or under the portion which is obstructed, and the west at that place is not at all interwoven with the warp. .
A knot or lump upon the warp, if not picked off, will often obstruct two or three threads, and form a small scobb. When the weaver, from inattention, continues to weave after a thread of warp has been broken, it very frequently crosses between a number of others nearest to it, and by obstructing the shed in that place, will cause a large scobb. Scobbs are also sometimes produced by the lay being too low or too high, but this is more frequent in weaving with the hand shuttle than with the fly. In this case the scobbs are always near the list or selvage of the cloth.
A second fault in cloth is known among weavers by the name of a jisp or shire. This is most frequent in light fabrics, and is occasioned by any particular thread of weft not being struck up so close as the rest. Jisps are very frequently occasioned by defects either in the construction or mounting of the loom. If either the yarn beam or cloth beam be not turned very true, jisping will be unavoidable, or if either the headles or the lay be not hung parallel to the beams, the same defect will ensue. If the loom is correctly made and mounted, the fault must be with the weaver, and this is only to be surmounted by attention and practice.
The other faults in cloth generally proceed from inattention in the management of the warp or weft. If threads are inaccurately drawn through either the headles or the reed, the defect will be apparent in the cloth.
There is nothing that adds more to the beauty of cloth of every description, and about which good weavers are more solicitous, than a tight uniform selvage. In order to produce this, the warp must be sized even with greater care than what is necessary in the middle of the web. The tightness of the weft, also, contributes materially to the beauty of the selvage. It is sometimes customary to warp a few dentfuls at each selvage with coarser yarn than the body of the web. In many kinds of cloth, however, the common practice is to draw the threads which form the selvage double. That is, to draw two threads through each headle.
The threads which form the warp of the selvage being coarser than the rest, and also being drawn more towards the middle of the web by the weft, the intervals of the reed through which they pass, are apt to be worn much sooner than the others. A weaver should carefully attend to this, for if the reed is injured, the work cannot be good. When cane reeds are used, and when the webs wrought in them are of one breadth, it is very common to make those dents between which the warp of the selvages passes, of brass or steel.
It is unnecessary to enumerate further, the defects which may occur in the weaving of cloth, for no instruction can altogether supply the want of skill, which is only to be obtained by practical crperience.
Having finished the foregoing general account of the nature and process of weaving, it now becomes necessary to pay some attention to the fancy and ornamental department of the business. Of fancy goods, many descriptions are woven in the common loom, without any additional apparatus, and with little, if any, variation from the process of weaving plain cloths. The extent to which this species of manufacture is carried, renders it an object of very great importance, and the variation in the operative part of the process is so small, that it may be introduced under the description of plain weaving, with little violation of arrangement.
As the thickness of the texture of plain cloth depends upon the proportion which the fineness of the yarn bears to the measure or set of the reed, it follows, that if yarns of different degrees of fineness are introduced at regular intervals into the same web, two distinct textures, or qualities of cloth, will be produced, and that the appearance of these will be different when the web is finished. Yarns of different colours may also be introduced, and when either of these is practised the goods are called
Stripes are formed upon cloth either by the warp, or by the weft. When the former of these ways is practised, the variation of process is chiefly the business of the warper, in the latter case it is that of the weaver. In extensive manufactories, where large quantities of striped goods of the same description are to be made, it common to form the stripes in the warping, because in this case, the stripes and their distances from each other will be uniform, which cannot be always relied upon where the stripes are formed by the weft.
In warp stripes, where the colour is the same, and the difference is in the fabric, the effect may be produced either by using yarns of different fineness, or by drawing a greater quantity of warp through a given number of headles or intervals of the need, where the stripes are to be formed. For example, two, or more threads, may be drawn through the same headle eye, or three, or more headlefuls may be drawn through the same interval of the reed, or thirdly, if the stripe is to be very thick, both these ways may be adopted.
CHECKS. The patterns of checks may be either similar, or dissimilar in the warp and west. The former is the most prevalent. Checks, being merely combinations of the two methods of striping, require no further description ; and as they contain, most frequently, a mixture of colours, their beauty depends more upon the taste and fancy of the manufacturer and the skill of the dyer, than upon that of the
weaver, whose business is merely to make the cloth of a good quality, and insert his weft according to the pattern.
Stripes and checks are manufactured in great quantities from all the different materials, especially from woollen, silk, or cotton. When the patterns of checks differ at the borders from the middle or bosom of the web, they are called shawls or handkerchiefs. It is very common to weave these with borders only, the bosoms being left plain ; in this case the check work is only at the corners, the
, rest of the four borders appearing as stripes, two by the warp, and
, two by the west.
WARPING OF STRIPED WEBS, &c. To compose a pattern for a striped web, you must begin by counting the number of threads in one stripe, then take half that number, if it is two threads per dent, if four, take the fourth of it; if 8 threads, š, &c., which will give the number of dents in a stripe. Measure the width of the stripe, so as to ascertain how many
times it is to be repeated in the breadth of the web. Multiply the number of times by the dents in the stripe, and you will have the entire quantity of dents in the web. Divide the number of threads in the web by 80, and as 80 threads is a porter, you will thus find the number of porters. The following example will explain this :
Suppose that one stripe contains 100 dents with three threads in each, and that there are 10 stripes in the whole breadth of the web, we may find the number of patterns or repeats thus :
100 dents in the stripe
10 repeats or stripes
3 threads per dent
40 threads over
By this we see that 3000 threads give 371 porters, 40 threads being half a porter.
This species of weaving derives its name from the French word touaille, and is generally confined to thick fabrics.
In analyzing the texture of plain cloth, it has been shown, that every thread of the warp and of the west cross each other at right angles, and are tacked together alternately. This is not the case in tweeling, for in this branch of weaving only the third, fourth, fifth, sixth, &c. threads cross each other. Tweeled cloths are produced of many different kinds. In the coarsest species every third thread is crossed, and this is commonly called the blanket tweel, in finer fabrics they intersect each other at intervals of 4, 5, 6, 7, or 8 threads, and in some silk stuffs the crossing does not take place until the 16th interval, which is denominated the full satin tweel.
Before proceeding further it may be proper to explain what is known among weavers by the appellation of flushing. When any thread or portion, whether of warp or weft, is not regularly interwoven in the cloth, as in plain weaving, that thread or portion of threads is said to be flushed. By referring to the following Figs. this will be more clearly illustrated.
In Fig. 13, which is referred to as a specimen of plain cloth, as it would appear when viewed through a microscope, the intersections of the threads are evidently alternate.