Fig. LXV.
1st, No. 1 leash in section 1.
2d, No. 2 leash in section 2.
3d, No. 3 leash in section 3.
4th, No. 4 leash in section 4.
5th, No. 5 leash in section 1.
6th, No. 6 leash in section 2.
7th, No. 7 leash in section 3.
8th, No. 8 leash in section 4.
9th, No. 9 leash in section 1.
And so on. The threading of the harness is explained below the comber-board, l and m indicating the leash-strings; and warp-threads 1, 2, 3, 4, from leashes 1, 2, 3, 4, are indicated as threaded.
384 times 4 divisions make 1536 warp-threads.
XII. Tying-up of Jacquard Looms with Compound Harness attached.
Tying-up of Jacquard looms with extra compound harness, consists in applying two separate systems of harness in the loom. The warp-threads, after having passed through the Jacquard harness, are passed through harness in front. Each system of harness performs special duty, although they are both working the same warp. The Jacquard harness is used for forming the general design on a large scale; the second harness divides this pattern into detail, (twills, satins, or any other desired weave). The above tie-up is necessary in the manufacture of rich damasks and similar fabrics, where a large number of warp-ends is required, with a correspondingly small number of picks per inch. Suppose a damask fabric to contain 300 ends warp per inch, with only 75 picks per inch; or in the proportion of 4 to 1. Now, to employ this principle of making four ends warp equal to one filling, the size of the design would be produced in the fabric, but the richness, and also the fineness, of the face of the fabric would be entirely lost. To prevent this it should be the object of the designer to keep the fine warp-threads entirely on the surface, to interweave the proportion of ends varying between warp and filling (as in example above, four warp-threads) separately. This principle of textures requires the compound harness to be attached; or, in other words, a machine must be used which is capable of raising not only every alternate thread, but every third, fourth, or eighth thread, if required, for the formation of the body of the cloth.
[Fig. LXVI.] illustrates as plainly as possible the principle of tying-up to do this work, using a 100 Jacquard machine for figuring, comber-board threaded in three divisions, four heddles to each leash, eight compound harnesses.
