Other Fancy Yarns.—Fancy yarns of an effective character may also be produced with simple modification in the normal carding and spinning processes. Thus "knicker yarns" are pro duced by throwing little bits of highly coloured material into the last cylinders of the card so that instead of being broken up by carding they are carried forward as "knickers" into the spun thread. "Random yarns" are produced by feeding the card with alternate stripes of dark and light material and taking the con densed slivers off with a zig-zag or moving-laterally doffer which takes sections of the lengths of its slivers from first one and then the other stripes. "Marl yarns" are produced by running two differently coloured slivers together on the roving frame just prior to the worsted spinning process, so that the colours are "regularly irregularly" mixed together.
If on the other hand a very level mixture effect is required dark and light coloured tops are mixed together in the worsted drawing processes, or, better still, the "tops" are printed the required col ours in bands and then passed through the worsted drawing proces ses this producing the extraordinary level mixture effect termed a "melange." Of the simple twofold yarns the best known is the "granderelle" in which a dark and light thread—usually of similar material, but not necessarily so—are finely twisted together as perfectly as possible. Another twofold twist termed a "spiral yarn" is formed by two single threads twisted in opposite direc tions being combined with twofold twist which necessarily shortens one of the threads by adding twist and markedly lengthens the other by taking out twist. Thus the slack thread "spirals" round the tight thread.
Yarn Effects and Special Properties.—The effects which may be produced by suitable selection of materials and yarn structure may be grouped into three classes, viz., light-reflective effects; form effects, and colour effects. Light reflection from the surface of a woven fabric depends upon the material or materials employed, upon the fibre arrangement in the thread, upon the thread interlacings and upon such modifications as may be intro duced in the finishing processes. Thus some wools are lustrous— the Wensleydale wool, for example—and some are opaque and dull—the Down wools. Ordinary cotton is dull, mercerized cotton is lustrous. A lightly twisted net silk yarn ("tram") is the most lustrous yarn known, while a specially hard twisted net silk yarn (crape) is the dullest yarn produced. Tram silk yarn interlaced on the "satin" principle produces the most lustrous fabric and crape silk yarn interlaced on the "crape" principle produces the dullest fabric known.
Merino wool spun on the woollen principle when woven into a normal fabric gives a dull surface but if the fibres are "raised" from the surface and laid parallel in the "finishing" processes then a brighter fabric may result than that produced from a merino wool spun on the worsted principle in which the fibres are laid parallel in the thread structure only.
The "form" effects will have been appreciated from the descrip tions already given of knop, curl, spiral, etc., yarns. These yarns specially coloured as already described offer the designer the oppor tunity of producing a never-ending array of novel fabrics. Should
specially white fabrics be required a "bleached" yarn is employed but it is more usual to bleach the material in the fabric state. Should a yarn which may be spun white but later—either in the yarn or cloth state—dyed two distinct colours be sought for, cotton may be blended with wool in the carding or in the draw ing processes, or strands of wool and of cotton may be twisted together and dyed distinctive colours later.
Yarn Counting and Numbering.—The numbering or "counts" of yarns, 30's, 40's, 8o's, etc.—may be explained best by the counting of woollen yarns. The basic weight is the "wartern" of six lb. the "quartern" of the old 24 lb. stone. This appears to have been a convenient weight for the spinners to take away to their homes for hand or "jenny" spinning. If this weight was spun in 1,536 yd.—that is each dram spun out to one yard—it was termed "one skeins." If one dram was spun to 2 yd., it was termed "two skeins"; if to 20 yd., it was "twenty skeins." Later it was found more convenient to deal with the unit weight of 1 lb., so that it has come to be usual to reckon the woollen "skein" as 256 yd. and the number of skeins to which a pound of this material is drawn out as the "counts," spoken of as "skeins" in the woollen districts. Thus if 1 lb. is drawn out to 5,120 yards (256X 20) the yarn is a "20 skeins." Unfortunately the woollen industry was spread over the whole of the known world before the unifying mechanical era dawned with the result that not only each country but each manufacturing district has adopted its own system of woollen yarn counting. Thus 200, 300, 420 yd. skeins are to be found and there is a still further complication in the United States where in one case the length is fixed and the count or skeins is given by the number of times the unit weight (the grain) is con tained in this unit length. This method is that natural to the net silk industry in which the drams per 1,000 yards, or the deniers (or decigram) per 450 metres gives the count spoken of as the "deniers." The cotton spinning industry which started from England adopted from the first a hank (or skein) of 84o yards and the hanks per lb. as the "count" and this has obtained world-wide acceptance. The worsted industry, apparently an off-shoot of the cotton industry, taking a yard instead of a i4 yard reel has adopted a hank of 56o yards and the hanks per lb. give the count. An attempt is now (1928) being made to adopt a universal system of counting yarns. The kilogram and the kilometre (or gram and metre) are suggested as the universal bases for everything except ing "thrown" silk and artificial silk yarns for which a base length of 50o metres is suggested and the weight of this in decigrams to give the "deniers" or "count." The yards to which one pound of material may be spun naturally vary with the fineness and nature of the material. Thus cotton has been spun on a commercial basis to 588,000 yd. per lb., linen to 18o,000 yd. per lb., worsted yarn to 56,000 yd. per lb., and woollen yarn to 15,00o yd. per lb. ; while net silk yarns, if required, may even be thrown finer than the finest cotton.