Fig. 131
Fig. 132
Designing.—When designing a pattern for gauze, with doups in front of the harness, it is only necessary to set off a few hooks of the jacquard to work the doups and slackener, and design the fancy portion on the remaining hooks; or if the gauze and slackener are wrought with tappets the full jacquard will be available for the figured portion, the same as if no gauze were being made. If the doups and slackener are to be wrought by the jacquard the pattern can be painted on the remaining hooks, and the dots for working these can be added afterwards, agreeably to the texture of the gauze required. The doup standard and slackener should act together, and the doup or half leaf should rise when the harness carrying the crossing threads rises. If the doup standard is to be raised every second shot, as is required when plain cloth has to be wrought with one doup, it might be wrought by a tappet, and the doup or loose heald might be raised by the machine for every shot, as it must rise with its standard as well as when the harness raises any of the yarn drawn into the doup. The doup shaft is best held down by a light spring. Indiarubber about 3/16 or 1/4 in. in diameter suits very well. One spring at each side of either one or two ply of this should be sufficient. If the number of rows in the harness is such that it will correspond with the number of threads to be twisted together, or be a multiple of them, it will be all the more convenient, though it is not necessary for it to be so. For instance, if 1 thread is twisted round 1, =2, an 8-row harness would give 4 repeats of this in each row; but if 1 thread were twisted round 2, =3, then 1 row of the harness would give 2 repeats, or hold 2 splitfuls of warp and 2 threads over, so that another thread would have to be taken from the back of the next row. For this a 6-row harness would be more convenient, which could be got by leaving 2 rows of the machine idle, and designing the pattern on 6-row paper, or ruling 8-row paper to 6-row after the design is painted. To work fancy textures with gauze by means of a harness with doups in front, both must be arranged to suit each other, unless a large number of doups be employed. For instance, a 2-and-2 twill could be wrought with 1 doup leaf in front of the harness by making 1 thread of the gauze twist round 3, and throwing 2 shots into each crossing, as shown in [Fig. 131]. If 1 thread were to be twisted round 1 with a 2-and-2 twill, and 2 shots to the gauze crossing, 2 doup leaves would be required, as shown in [Fig. 132]. A 4-thread fancy twill can be wrought with 1 doup, as shown in [Fig. 133], 1 thread twisting round 3 and 4 shots into each crossing of the gauze. Satins or regular twills are more difficult to work, unless by making an irregular gauze. Take a 5-end satin, which has the threads over 4 and under 1. The gauze might have 4 shots and 1 shot into each crossing alternately, and be easily wrought with 1 doup; but if 2 or 3 shots had to go to each crossing it would be different, as the doup would require to sink for 1 shot out of 5, in order to let the threads drawn into it bind in the twilled portion of the cloth, or otherwise the binding would have to take place on these threads when the doup is down, which it could do if it suited otherwise. But it must be remembered that when solid cloth and gauze are working together, the former is made by raising the doup standard and those mails which carry the threads that are not drawn into the doup, leaving stationary the mails carrying the crossing threads, except where gauze is being made; therefore, in working a 5-end satin, if the doup held up any of the threads for, say, 3 shots, and then sank for 3, there would be no way of holding up these threads in the twill portion to make them pass over 4 shots, as a 5-end satin must do, for if the harness twines carrying these threads are raised, they will cause a cross to be made instead of completing the twill. Patterns of this description should all be wrought in a gauze harness. In the figures given the gauze crossings are represented by dotted lines where they are raised by the harness, for sake of distinction.
Fig. 133