Power great development in the art of weaving followed upon the invention of the power loom by the Rev. E. Cartwright in 1784. In the power loom, which has been gradually improved and adapted to steam and electric power, the principal motions of the old method of weaving, such as shedding the warp threads, throwing the shuttle, and beating up the thread, are still retained. The frame of the power loom is of cast iron, and motion is com cessively lifted and lowered is determined by means of a series of pasteboard cards punctured with holes, the holes corresponding to a certain pattern and the cards passing successively over a so-called "cylinder," of square cross-section, over which the chain of cards is carried. With each pick of the shuttle this "cylinder" swings outward and makes a quarter-revolution pre senting a new card face on the return swing. The wire rods which fail to strike a hole in the card are driven back thus unhooking the hooked rods from the rising and falling "knife municated to the loom by means of a shaft, the stroke of the ley being made by cranks attached to the driving shaft, while the shuttle is thrown by means of a lever at the centre of the loom. Although the principle of the loom is the same in all kinds of weaving, yet there are number less modifications for the production of special fabrics. The lappet loom may he employed for weaving either plain or gauze cloths, also for putting in representations of flowers, birds or the like, with the effect of embroidery.
Cross Weaving is a term applied to that process in which, as in gauze weaving, the warp threads, instead of lying constantly parallel, cross over or twist around one another, thus forming a plexus or interlacing independent of that produced by the weft. It is a combination of knitting and weaving.
Double Weaving consists in weaving two webs simultaneously one above the other, using two sets of warp threads from two warp beams. and interweaving the two at intervals so as to form a double cloth. Kidderminster or Scotch carpeting is the chief example of this process. Three-ply and four-ply cloths are similarly made. The plan of make-up of these fabrics is illustrated in Fig. 14.
Pile Weaving is the process by which fabrics like that of velvets, velveteens, corduroy and Brussels carpets are produced. In the weaving of these fabrics, besides the ordinary warp and weft, there is what is called the pile-warp, the threads of which are left standing in loops above the general surface until cut, and the cut ting of which produces the pile. In such fab rics as Brussels carpet the loops are left uncut. The manner in which the pile-warp is woven into the fabrics is illustrated in Fig. 15. See Loom ; VELvEr.