When the loom is running, the Jacquard lifts one worsted thread in each reed, thus forming a shed, under which the wire is introduced from the side. Immediately below the wire now lies the body of the fabric, consisting of the four frames of worsted in each course, which are not required to form the pattern, the stuffer warp, and one half of the cotton chain. Below the body of the fabric is a lower shed formed by the other half of the cotton chain, and through this the shuttle passes, carrying the weft, at the same time as the wire is being inserted. Then the lathe, which has been lying back to allow the passing of the shuttle and the entrance of the wire, comes forward with the sley, and beats up the wire and the last shot of weft against the breast-plate of the loom and the last part of the woven fabric. At the same time the Jacquard allows the harness carrying the ends selected for the last lash to drop back on to a level with the others, and the gears carrying the cotton chain begin to change. Next, the lathe goes back again; one half of the chain is brought up to form a shed, under which and over the rest of the threads the shuttle passes back, thus effectively tying in the worsted threads which are looped over the wire. Meanwhile the last wire of the set (of about 30) which has moved forward as the fabric is woven, is drawn out by a hook, and carried back for insertion under the next shed of worsted. A number of wires is used so as to avoid the risk of the loops being pulled flat by the weight on the yarn or the strain of the harness or sley. Chains and stuffers are generally coloured and sized, the yarn being slowly wound from bobbins or cheeses on a frame or stand, passing through a trough of coloured starching material, over a steam-heated cylinder, or a series of pipes, on to an iron flanged beam. The weft, which is normally of linen yarn, is also generally coloured and sized, and is used whilst still damp. The colouring certainly adds to the appearance of the carpet, and the sizing adds stiffness and handling, though, apart from this, and from the fact that it is expected by the dealer, it is doubtful whether it is of any advantage, except in the cheaper grades, where less yarn is used.