The gauze harness which will probably be most frequently met with, at least in the cotton trade, is shown in [Fig. 138]. It is an older harness than that described, having been patented in Macclesfield in 1876 in a somewhat different form. The difference between this and the preceding chiefly consists in the method adopted for slackening the yarn, and the jacquard may also be specially built to suit for this. In setting this loom the harness and mails are tied up and levelled as before, but when working the back rail is kept down, as it usually is for gauze work, say about 1/2 in. lower than the eyes of the mails. Each whip thread has its own slackener, the slackening apparatus consisting of a harness wrought either by the same jacquard that works the figure, or by an extra one, when much pattern is required.
The connections of the needles with the hooks are shown at A, the two bottom needles being connected with the two front and two back hooks, the former for working the gauze and the latter for working the slackeners. This harness is intended for a 1-round 3-gauze, and is mounted on a 10-row machine with an 8-row cylinder on it. It is not necessary that the back harness for slackening should be raised so high as the figuring harness is, and for this reason, as well as that it makes the harness more direct and avoids friction, it is tied to two sets of levers as shown at G and G1; they are made of brass and are fastened on two rods, one about 4 in. above the other, so as not to come into contact with each other when rising or falling. The points of the levers are fastened to the two back rows of hooks as shown, and the harness is tied to wire hooks on these levers; F is the neck of the harness, D the cumber board, and N the lingoes, which are much heavier than those used for the figuring harness, from 6 to 10 per pound being the weights frequently used, according to the class or weight of the work.
The mails used on the back harness are similar to those used for the doups—that is, such as are shown at No. 1 ([Fig. 138]); but if these cut with the warp sawing through them, glass mails should be used. L L1 are two rods or bars which support the warp that is drawn down between them by the slackening harness. The closer these bars are set together the greater will be the amount of slackening given to the warp when the harness is drawn; therefore these bars should be made to slide either way so that the desired slackness is obtained by setting them. About 3 in. to 4 in. apart is a good working width; the tops of the bars should be about 1 in. lower than the mails in the figuring harness, and the tops of the eyes of the mails in the back harness should be 1 in. or 1-1/4 in. lower than the rods.
Another method of arranging the needles in a jacquard for a gauze mounting is shown in [Fig. 139], which is, perhaps, more convenient for the designer, as will afterwards be seen. In this harness there are 10 rows of hooks, the same as before—6 for the figuring harness and 2 for the doup standards. The doup standards are here on the hooks connected with the fourth and eighth needles, and come after the threads that the whip in them twists round, and fall in this position on the design paper, instead of both being at the end of a design—that is, on the seventh and eighth checks. For any order of twisting, the arrangement of the hooks and needles might be made to suit on the same principle.
It will be seen that in the leno jacquard, shown in [Fig. 138], a number of levers and attachments are required to work the slackening harness. In order to simplify this, Messrs. Devoge & Co. have brought out a leno jacquard with which none of these levers, &c., are required, the slackening harness being tied to the two back rows of hooks in the machine. These two rows of hooks are lifted by a separate griffe, the lift of which is much less than that for working the body hooks of the machine, and which can be varied to suit the amount of slackening required. This machine is shown in [Fig. 140], a view of the motion for raising the griffes of both back and body harness being given in [Fig. 140a]. c d ([Fig. 140a]) is the link connection between the bar of the griffe a a and the top lever L ([Fig. 140]), somewhat similar to what is used for an ordinary jacquard. To raise the small griffe at the back, it will be seen that there is a cross lever e from the links d, c to its fulcrum h on a bracket g attached to the top of the machine. The small or back griffe b is connected to this lever by the link f. The amount of lift given to the small griffe in proportion to that given to the large one will be as the length of the lever from the stud in h to that in f is to its length from the stud in h to that in d. The farther the fulcrum is pushed back in the slot in which it is fastened, the more the back griffe will be raised, the link f being always vertical. The back griffe is arranged to commence lifting slightly in advance of the front one, in order to lessen the strain on the doups. The needles are connected with the back and front hooks in this machine similarly to those in [Fig. 138].
Fig. 139
The draft of a gauze in the harness is just the same as regards the doups as for shaft work; the crossing may be made from left to right, or the reverse, but the pattern must be made to suit. Some mount the harnesses and paint the patterns from right to left. About Bradford this appears to be the usual method, and it does not matter provided the mounting, drawing and designing be kept in accord; but here we shall keep to the same principle as is recognised all through—viz. mounting and designing from left to right, which is the correct method so far as drawing is concerned, and equally convenient in other respects.