Page:Encyclopædia Britannica, Ninth Edition, v. 14.djvu/202

 190 LACE to show effects obtained by varying the tensions of weft and warp threads. For instance, if the weft, as threads b, by b, b in fig. 27, be tight and the warp thread slack, the FIG. 29. Section of Lace Machine. warp thread a will be twisted upon the weft threads. But if the warp thread a be tight and the weft threads b, b, b, b be slack, as in fig. 28, then the weft threads will FIG. 30. Pillow-made Lace. Mechlin. Early 18th century. be twisted on the warp thread. At the same time the twisting in both these cases arises from the conjunction of movements given to the two sets of threads, namely, a movement from side to side of the beam or warp threads, and the swinging or pendulum-like oscillations of the bobbin or weft threads between the warp threads. Fig. 29 represents a section of part of a lace machine. E is the cylinder or beam upon which the lace is rolled as made, and upon which the ends of both warp and weft threads are fastened at starting. Beneath are w, w, iv, a series of trays or beams, one above the other, containing the reels of the supplies of warp threads ; c, c represent the slide bars for the passage of the bobbin b with its FIG. 31. Machine-made Imitation of Mechlin Pillow Lace. thread from k to k, the landing bars, one on each side of the rank of warp threads ; s, t are the combs which take it in turns to press together the twistings as they are made. The combs are so regulated that they come away clear from the threads as soon as they have pressed them together and fall into positions ready to perform their pressing operations again. The contrivances for giving each thread a particular tension and movement at a certain time are connected with an adaptation of the Jacquard FIG. 32. Venetian Point Lace, a roseau. 17th century. system of pierced cards. The machine lace pattern drafter has to calculate how many holes shall be punched in a card, and to determine the position of such holes. Each hole regulates the mechanism for giving movement to a thread. Fig. 30 is a specimen of a Flemish pillow lace of the early 18th century. The meshes of the ground are variegated in appearance. A thread outlines the pattern. In fig. 31 it will be seen that the manufacturer has merely attempted to reproduce the pattern of the foregoing. His meshes are regular. No outlining thread marks the pattern, which, instead of being filmy, like cambric, is ribbed. This speci-