Having given a general outline of the nature and process of plain weaving, it is necessary, in order to convey to our readers a more comprehensive idea of the art, to notice the fanciful and orna mental parts of the business. The extent to which this species of manufacture is carried renders it an object of very great importance, and deserving a more minute description than our limits will admit.
Stripes are formed upon cloth, either by the warp or by the woof. When the former of these ways is practised, the va-' nation of the process is chiefly the busi ness of the warper in the latter case it is that of the weaver. By unravelling any shred of striped cloth, it may easily be discovered, whether the stripes have been produced by the operations of the warper or those of the weaver.
Checks are produced by the combin ed operations of the warper and the weaver.
Tweeted cloths are so various in their textures, and at the same time so compli cated in their formation, that it is impos sible to convey an adequate idea of the mode of constructing them, without the aid of several engraved figures. In exa mining any piece of plain cloth, it will be observed, that all the threads in the warp and woof cross each other, and ed alternately. This is not the case in tweeled cloths ; for in this instance only the third, fourth, fifth, sixth, &c. threads cross each other to form a texture. Tweeled cloths have been fabricated of various descriptions. In the coarsest kinds every third thread is crossed ; in finer fabrics, they cross each other at in tervals of four, five, six, seven, or eight threads, and in some very fine tweeled silks the crossing does not take place un til the sixteenth interval.
Tweeling is produced by multiplying and varying the number of leases in the harness ' • by the use of a back-harness, doubleor double harness ; by increasing the number of threads in each split -of .the reed; by an endless variety of modes in drawing the yarns through the harness ; and by increasing the number of tred dles, and changing the manner of tread ing them. When the number of treddles requisite to raise all the variety of sheds necessary to produce very extensive patterns would be more than one man could manage, recourse is had to a mode of mounting, or preparing the loom, by the application of cords, &c. to the har ness; and a second person is necessary to raise the sheds required, by pulling the strings attached to the respective leases of the back harness, which are stink to their first position by means of leaden weights underneath. This is the most comprehensive apparatus used by weavers for fanciful patterns of great ex tent, and it is called the draw-loom. In weaving very fine silk tweels, such as those of sixteen leases, the number of threads drawn through each interval of the reed is so great, that, if woven with a single reed; they would obstruct each other in rising and sinking, and the shed would not be sufficiently open to allow the shuttle a free passage. • To avoid this inconvenience, other reeds are placed behind that which strikes up the weft ; and the warp threads are so disposed, that those which pass through the same interval in the first reed are divided in passing through the second, and again in passing through the third. By these
means the obstruction, if not entirely re moved, is greatly lessened.
In the weaving of plain thick woollen cloths, to prevent obstructions of this kind, arising from the closeness of the set, and roughness of the threads, only one-fourth of the warp is sunk and raised by one treddle, and a second is pressed down to complete the shed, between the times when every shot of weft is thrown across.
Double cloth is composed of two webs, each of which consists of warp ' and separate weft ; but the two are inter woven at intervals. The junction of the two webs is formed by passing each of them occasionally through the other, so that each particular part of both is some times above and sometimes below.
This species of weaving is almost ex clusively confined to the manufacture of carpets in this country. The material employed is dyed woollen ; and, as al , most all carpets are decorated with fanci ful ornaments, the colours of the two webs are different, and they are made to pass through each other at such intervals as will form the patterns required. Hence it arises, that the patterns of each side of the carpet are the same, but the colours are reversed. Carpets are usu ally woven in the draw-loom.
Gauze differs in its formation from other cloths, by having the threads of the ' warp crossed over each other, instead of lying parallel. They are turned to the right and left alternately ; and each shot of weft preserves the twine which it has received. This effect is caused by a sin gular mode of producing the sheds, which cannot easily be described withow the aid of drawings Cross, or nemveating, is a ser‘ore branch of the art, and requires loom particularly constructed for tbo purpose.
Spots, Brocades, and Layets, are pro dosed by a combination of the arts of plain, twecled, and gate:e weaving ; and, as in every other branch of the art, are produced in all their varieties by differ ent ways of terming the sheds, by the ap plication of baffles. and their connec tions with the treddles which move them. Indeed, the whole knowledge of the art consists in this part of the apparatus of a loom.
In drawing up the foregoing account of the art of weaving, we have laboured un der inconveniences of no small magni tude. The many different kinds of cloth ; the almost infinite variety of ways, though all on the same general principle, of constructing them ; the different for mation of apparatus in making different cloths ; and, lastly, the want of uniformi ty in the technical phraseology of the art, have all tended to render our de scriptions far more intricate and difficult than they otherwise would have been. The assistance, however, which we have derived from the very excellent "Essays on the Art of Weaving," by Mr. Duncan, ought not to pass by us unacknowledged. It is a most curious and valuable publica. tion, embracing almost every thing ne cessary to be known concerning the art on which it professes to treat.