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 weft.

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,, &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 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:

number of porters.

By this we see that 3000 threads give 37 porters, 40 threads

being half a porter.

SECTION SECOND.

TWEELING.

TWEELED CLOTH.

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 thread of the warp every and of the weft 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.

Fig: 13.

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.

Fig. 14 may be considered as a representation of tweeled cloth, upon the same principle that Fig. 13 represents plain. This fig. will show that the same thread of weft remains flushed or disengaged from the warp while passing over three threads, and is tacked down by passing under the fourth. Now, were this cloth turned upside down, the same appearance would take place in the warp. That is to say, every fourth thread of the warp would be interwoven with the weft and the remaining three threads would be flushed. An inspection of the Fig. will also convince the reader, that the threads, both of the warp and weft, are interwoven at regular intervals.

To produce these effects a number of leaves of headles are required, equal to the number of threads contained in the interval between each intersection, inclusive. Thus, when every third thread is to be interwoven, three leaves are required; if every sixth thread, six leaves will be necessary; and so of all the others. For this reason, the different species of tweels are distinguished by the number of leaves which are requisite in weaving them, as a four, five, or six leaf tweel, &c. The specimen in Fig. 14 is a four leaf tweel.

Tweeling is, in many instances, applied to the weaving of cloths which require a great portion of strength, thickness, and durability.

In the silk manufacture tweeling is very common. Sometimes it is employed for the sake of strength, but more frequently for the display of colour. In the woollen, strength is the general object, and in the cotton it is most commonly the same.

It may be necessary in this place to enquire into the causes which render tweeled cloths stronger than plain, and to ascertain the difference.

In so far as the strength of tweeled cloths depends solely on the mode of weaving, that strength will be rather diminished than increased, when compared with plain cloth, containing an equal quantity of similar materials. For in the texture of plain cloth every thread is alternately interwoven, while in that of tweels they

are only interwoven at intervals. Now, in the latter case, the threads can derive no mutual support from each other, except at the intervals where they are interwoven, and that part of them which is flushed must depend entirely on the strength of the individual threads, those of the warp being flushed upon one side, and those of the weft upon the other.

The following inference will naturally arise from this: let two webs of equal length, breadth, quantity, and fineness of yarn, be woven; let the first be plain and the second tweeled, and their strength ought to be the same. But if by strength, we understand that property which opposes the most effectual and most continued resistance to the decay of cloth, from common wearing, the tweeled web (if equally used) would be in tatters long before the plain one would be materially injured. This is the idea commonly, although inaccurately, attached to the word strength when applied to the texture of cloth; and, indeed, the above remark will not be found universally true, for the durability of cloth exposed only to common wearing, depends partly upon its strength, and partly upon its flexibility.

It is not, therefore, in the effect of the mechanical operation, but in the facility of combining a greater quantity of materials in the same space, which this mode of weaving affords, that we are to look for superior strength or durability. This may be easily illustrated when the shed of any web is opened, every thread of warp, either above or below the thread of weft, will oppose a certain resistance to the operation of the reed in driving the weft thread home, and the sum of all these will be the total amount of resistance. Now, in plain weaving, as before stated, every thread is alternately interwoven, and therefore, opposes its portion of resistance; whereas,

four leaf tweel every fourth thread only is intersected, and of course, less resistance is given. The ratio of resistance, therefore, will be inversely, in proportion to the number of leaves of headles in the tweel.

In the warp the friction on the reed will be diminished, in the same proportion; for each warp thread, instead of changing its place every time the weft thread crosses, changes only once every four times; consequently, much more warp may be crowded into the same space than could be done in plain weaving.

From the above we may safely deduce, that the strength or durability of a tweeled web, will be somewhat less than the proportion of materials it contains will be to that of a plain web, supposing each to be of equal strength and quality.

But when the fabric is very close, tweeled cloth possesses another advantage over plain in point of durability. When the warp of plain cloth is very much crowded in the reed, and the weft driven very closely up, the threads, in order to cross each other alternately, must deviate very considerably from a straight line, whereas, when woven they become serpentine. This renders the cloth very liable to be easily cut or chafed, especially when composed of hard and comparatively inflexible materials, such as flax; and the defect is chiefly observable in stout linens. But in tweeled cloth, as the threads only cross at intervals, the deviation from the straight line is much less, and the flexibility of the cloth, of course, much greater. The same general remarks which have been given in the first section, apply almost equally well to the operations of the weaver in all descriptions of work. The varieties consist, chiefly, in the modes of arranging the loom, so as to enable the weaver to produce the desired effect.

MOUNTING OF LOOMS FOR TWEELING.

As almost every variety of fancy weaving is produced by the order and succession in which the weft is interwoven with the warp, the principal difference in mounting the looms is in the number and arrangement of the leaves of the headles, and the apparatus for moving them. In weaving plain cloth, the jacks represented in Fig. 8, at FF, answer the purpose sufficiently well, because the raising and sinking of every thread is alternate. But, in the weaving of tweels and many other kinds of ornamental and fancy cloth, the number of leaves is generally greater, and these are to be raised and sunk successively, or not, as the nature of the case may require. It is therefore necessary, that the mounting of the loom should be adapted to the purpose for which it is intended, and as the succession of working the headles by means of the treadles may frequently vary, the mounting which connects every leaf with the treadle, and from which its motion is derived, must be such that the leaf may be raised or sunk independent of all the others. A representation of the mechanism used for this purpose, by many skilful weavers, will be found in Fig. 15.