chain-stitch is not greater than that of the single-thread chain-stitch in silk only. The former is also infinitely to be preferred to the latter where durability is required; as although in the case of a stitch being dropped, it would be possible to unravel that portion of the seam which was already completed, the seam seldom comes undone through wear alone of the article sewn. An imperfect stitch may occur in two ways; either the loop of the lower thread c (Plate I., Fig. 18) is not caught by the succeeding one of the upper thread, in which case the seam would not of itself come undone, the loop e being held by the loop c, which is again held by the loop e, being tightly drawn together; or the loop of the upper thread is not caught by the succeeding one of the lower thread f, and in this case the loop b would be entirely drawn out of the material by the tension of the upper thread, as would also the loop f by that of the lower thread causing the stitch g h double the length of the other stitches, and containing the same imperfect stitch d, already described, which does not involve a further unravelling of the seam. The double-thread chain-stitch can, therefore, very well be applied where durability and strength are required for articles of dress, caps, cloth boots, gloves, &c.; it is also frequently made use of in sewing stays, both for its appearance and strength. The lower side is generally employed in the decoration of mantles, caps, ties, gloves, &c., as from the employment of two threads, a variety in colour may be produced, as may also the effect of braiding by taking the lower thread of sufficient thickness, and allowing the tension to be as slight as possible. The thickness of the seam on the wrong side, which causes

articles of dress to wear soon out at the point of connexion, is diminished by using very fine cotton for the lower thread, so that the chain has almost the appearance of a single thread.

The quilting seam is the most perfect which can be produced by the sewing-machine. The advantages of the single and double-thread chain-stitch, are retained without their inconveniences. It is true that should the lower thread, which passes through all the loops of the upper one, be drawn out, the whole seam would become unravelled. But we are enabled, by means of the loops of the upper thread, to draw the lower thread into the material to be sewn, when the seam presents the appearance shown (Plate II., Fig. 16 to the right-hand side), which is the true machine quilting, or back-stitch seam, that can no longer come undone. This further advantage is also gained, that the seam is alike on both sides. An imperfect stitch can also occur in this description of seam, from the lower thread not passing through the loop formed by the upper one, which is then drawn back out of the material, causing a stitch double the length of the others, without in any way impairing the durability of the seam. The thread consumed by this description of seam is proportionately small, about 21 times the length of the seam itself. The stitches being moderately long, and the material not too stout, the proportion of thread consumed by quilting, single and double-thread chain-stitch seams, may be taken as 2, 3, 4. Another quality in favour of the quilting-stitch. This stitch is, therefore, the most extensively employed, both for ornamental and durable work-for shirts, coats, dresses, caps, gloves, stays, shoes, saddles, in fact, for every

description of sewing. These seams are all fastened off by enlarging the last loop of the upper thread, drawing it through the needle-hole, and tying it to the lower thread. In the quilting-stitch seam, 3 or 4 stitches backward answer the same purpose.

THE FORMATION OF THE STITCH.

The needle employed in machine sewing differs from that employed in sewing by hand, as instead of having the eye at the head of the needle, it is constructed close to the point. The machine needle consists, therefore, of a short conical point and a long cylindrical body. The point must not be too stout, as it would otherwise meet with too much resistance in its passage through leather, pasteboard, &c. A special apparatus for piercing the holes. for the passage of the needles is no longer employed, and the needles are now constructed angular, with two, three, or four sides for heavy work. The twoedged needle has, perhaps, come most into use, the flat sides of which have a direction diagonal to that of the seam, and the stitches also have this direction, so that the seam resembles the saddler's seam (Fig. 23). The length of the point of the needle (reckoning from the eye) varies from to in. Circumstances at times require a longer or shorter point, but as a rule, short points are to be preferred, as a long point requires a longer stroke of the needle, which is disadvantageous in a machine which is required to work with rapidity. On the other hand, long points have the advantage of allowing of their being re-ground when blunt. The eye of the needle is a cylindrical hole, the outer edges of which are rounded off. It is important that the interior sur

face of the eye should be perfectly smooth, so that the thread, which does not as in hand sewing retain a fixed position in the eye, but passes backwards and forwards in it at each stitch, should not become frayed by the constant friction, and at last break. The eye must also on this account be made proportionately large, and its edges rounded off, giving to it the appearance of being conically enlarged on each side. Fig. 24, in Plate II., shows a perfectly cylindrical eye (ƒ) on an enlarged scale, in which the thread evidently suffers more from friction than in the conically enlarged eye (c).

The eye being larger in proportion to the thread than that of the common sewing needle, and the size of the body of the needle being conditional on the size of the eye, the exterior of which must be made sufficiently stout as not to weaken the needle, it follows that for thread of a given thickness a stouter needle must be employed in machine than in hand sewing. Owing to this the hole made by the needle is too large in proportion to the thickness of the thread, which though unimportant for soft materials, as cloth, silk, cotton goods, &c., is a great objection when the material is tough and hard, as leather. Especially when the stitches are very small the material is apt to rip in the direction of the seam. In the seam made by shoemakers, by means of an awl, the thread not only entirely occupies the space made by the awl, but is actually compressed into the puncture, while the thread of a machine-made seam has always more or less play in the hole made by the needle. In order to assist the passage of the needle, with the thread on each side of it, through the material, the needle is grooved on both sides from the eye as far as

the needle penetrates. The length of this groove is from 7 to 11", according to the construction of the machine. The depth depends naturally on the stoutness of the needle, but is always made as deep as possible without impairing the strength of the needle. Sometimes the groove is continued on towards the pointto", as on the withdrawal of the needle from the material the thread lies close to the needle in the direction of the point. (See Fig. 21, a e.)

The needle is affixed to the so-called needle carrier, the distance of the eye from which varies according to the construction of the machine. As a rule, the distance should be as short as possible, never exceeding 1 in., except in machines in which very stout needles are employed, as the shorter the needle the greater strength it possesses. That part of the needle fitting into the needle carrier is generally somewhat thicker than the rest, and is made of the same thickness for needles of all dimensions. This arrangement imparts greater strength to thin needles, and also allows both thick and thin needles to be so inserted that the points of either move up and down in a certain fixed straight line. Many needles are, however, made without being thus strengthened, owing to their greater cost, whether constructed of one piece or with a shank soldered on. The steel of which the needles are manufactured must not be so hard as to allow of their easily breaking, but must possess sufficient elasticity to prevent their becoming bent. The shank only, which is inserted in the needle carrier, is usually made softer. The thickness of the needles varies from to in., according to the description of thread