The sliding bar of the lappet motion may vary slightly in its movements so that the needles will not always pierce through at exactly the same points at each repeat of the pattern, although the general design will be maintained. The threads which feed the needles should be of good clear ply material, free from slubs and irregularities, so that they will pass freely through the needle eyes, and they should have enough turns to enable them to withstand the friction resulting from the backward and forward sliding movements of the lay passages. The yarn must be delivered from independent spools, which work with perfect freedom, and measures should be taken to control the stock by the use of delicate springs. The material used for the lappet figure is perhaps best run from grooved spools which are so weighted that they feed easily through the needles at every forward movement of the lay. PEARL EDGE An effective and inexpensive method of elaborating a silk frill is found in what is known as the pearl edge. This adds much to the richness of the goods, besides giving the appearance of greater width at slight increase of cost. The pearl edge is produced by a series of fine steel edge wires, which are carried in separate dents of the front reed outside of the frill itself. Each wire is operated by a special harness which brings it into the weaving lines as desired, so that the filling may pass around it and make pearl loops at these particular places. It will be found necessary to use hard steel dents in the front reed to work the wires in, otherwise the dents will soon be cut from the constant wear of the wires. A silk frill may also be much enriched by special fancy drafts. These allow for the operation of groups of threads so that the filling passes over and under them and show up the luster of the silk filling in blocks contrasting with the more plainly woven parts. An example of this is shown at Fig. 6. CHAPTER VIII. _Designs Produced by Use of Jacquard in Connection with Cams or Head Motion—Weaving Buttonholes in Webs—Manufacture of Surgical Belts and Bandages—Combination Woven and Printed Designs—Method of Printing_ In previous articles we have confined our remarks to the production of elastic fabrics on plain and fancy looms. These machines are more or less limited in capacity, and the stock must be operated in groups of threads. Considerable care is necessary in the selection of patterns best adapted to these looms. In jacquard weaving each separate thread is controllable, and the scope of pattern and design is limited only by the space available on the face of the fabric.