B. THE VARIOUS DESCRIPTIONS OF MACHINE SEAMING THE FORMATION OF THE STITCH THE SINGLE-THREAD CHAIN-STITCH THE RECIPROCATING HOOK THE ROTATORY HOOK 2. THE DOUBLE-THREAD CHAIN-STITCH . THE QUILTING-STITCH 1 ib. 5 14 19 20 21 23 28 SHUTTLES FOR HORIZONTAL CURVILINEAR MOTION. II. THE MECHANICAL ARRANGEMENTS OF THE SEWING MACHINE 40 41 46 THE STITCH REGULATOR D. THE TENSION APPARATUS TENSION BY FRICTION OF THE THREAD TENSION BY FRICTION ON THE SPOOL TENSION BY A ROLLER THE THREAD GUIDE III. THE SEWING MACHINE. A. THE MACHINES WITH OSCILLATING LOOPER FOR SINGLE-THREAD THE SINGLE-THREAD CHAIN-STITCH MACHINE WITH ROTATING HOOK. 84 86 D. MACHINES FOR QUILTING-STITCH, WITH MOVEABLE SHUTTLES 92 93 THE SEWING-MACHINE. I. THE FORMATION OF THE SEAM. A.- -THE HAND SEAM. The THE seam, formed by hand, by means of a needle and thread, is generally intended to connect two pieces of material, either in a straight or curved direction. The construction of the seam itself varies according to the purpose of its application. The three principal varieties are: 1. The tacking, or chain-stitch seam. 2. The whip, or overcast-stitch seam. 3. The quilting-stitch seam. latter description of seam (Plate II., Fig. 17) varies in appearance on each side of the material, as on the one side each stitch adjoins the other; while on the reverse, each stitch covers half of the preceding one. A variation of the quilting-stitch is the back stitch (Fig. 18), the derivation of which from the former is evident, by imagining between each two stitches a vacant space on the one side of the material of the length of a single stitch, causing each stitch on the other side only to cover a third of the preceding one. The whip-stitch seam consists of a series of stitches running spirally round the B |