Gauze and Leno Cloth.
This class of fabric is frequently woven by means of the dobby, although the tappet and jacquard are occasionally used should the pattern come within the scope of either. The peculiarity of gauze is, that some of the warp ends cross over one or more of the other warp ends between the picks, giving an open fabric, sometimes of a beautifully delicate nature, and yet strong, considering the small amount of material used. When gauze weaving is combined with plain it is styled leno. The latter name is sometimes erroneously attached to the gauze itself.
FIG. 54.
[Fig. 53] shows a pure gauze in plan, and [Fig. 54] the same in section.
FIG. 55.
[Fig. 55] is the plan of a leno. The threads marked heavily in each case are the crossing threads. It will be noted from [Fig. 54] that the crossing thread passes up alternately at each side of the backing thread, pick by pick.
The operation of crossing is performed by doup healds. In these an additional loop or half heald carrying a stave at the bottom is slung through the eye of an ordinary heald ([Fig. 57]). For the purpose of description, the whole of this heald will be termed the doup. This heald is used for crossing purposes, while two or more ordinary healds are provided for the purpose of varying the working, if necessary. The draft for cloths, [Figs. 53] and [55], is as shown by [Fig. 56]. The crossing thread is drawn through two healds and passes under the backing thread as shown.
FIG. 56.
FIG. 57.
However, the heald No. 2 can be used to raise the crossing thread on the left-hand side of the backing thread, although it is drawn to the right of it at the front, as whenever the back heald is lifted, the loose stave of the doup is lifted also, and the crossing thread is thus free to be wrought by No. 2.
The weaving of the plain is performed by either No. 2 and the doup, or by Nos. 1 and 2. In weaving the gauze portion, healds No. 1 and the doup are used only.
Four jacks are required—one for the back heald, one for No. 1 heald, one for lifting the whole doup when weaving gauze, and a fourth for raising the half loop when necessary to release the crossing thread.
To weave the design [Fig. 55] with the given draft, at the bottom pick No. 2 heald and the loop will be raised, at the next pick above the whole doup requires lifting, at the third No. 2 and the loop, at the fourth the doup, at the fifth No. 2 and the loop, at the sixth the plain commences and the doup is raised, at the seventh No. 1 is raised, eighth the doup, ninth No. 1, tenth the doup, which completes the pattern, the eleventh being a repeat of the first.
It is not necessary that the crossing should be round one thread only, but may be round three or four; to do this, of course, the crossing thread would have to be drawn under three or four backing ends in the healds.
The crossing may also be in opposite directions, say—
FIG. 58.
as in [Fig. 59], where the crossing thread passes over two backing ends. Every alternate end is, in this case, douped contrarily, the same healds being used—the difference being made in the draft. This style is called netting.
All the patterns hitherto mentioned have been single doups. A more highly-ornamental class of goods is made in double-douped cloth. Here two-doup healds are used, and, consequently, half of the crossing threads may be weaving plain at the same picks that the others are douping, and then a reversal is made—the first half commencing to doup while the other section is weaving plain. Thus, check patterns are made alternately gauze and plain. Double-douped netting and stripe patterns may also be made. With a single doup, only stripe patterns may be produced with the gauze running either transversely or longitudinally. For more complicated patterns three or even four doups are employed.
FIG. 59.
Gauze patterns are not generally marked on paper as are other fabrics, but sketched thus:—
FIG. 60.—GAUZE SKETCH.