Shantung, or true pongee, can be readily distinguished from the imitation by examination of the threads, both warp and filling. These should be very long, and loosely spun or rather “thrown,” whereas the imitation threads are spun together tightly, from fibres of many different lengths, generally quite short. Preparing Silk for Dyeing. _Reeling._—All silk, whether cultivated or wild, comes originally from the cocoons, which are, as a rule, each formed out of a continuous strand or thread woven by the silkworm round and round its own body before it passes into the chrysalis state. These cocoons are collected, carefully dried to kill the quiescent animal inside, and then, in due course of time, they are placed in basins of warm water which softens the gum which binds the cocoon threads together, and the separate fine threads from several cocoons are picked up by brushing, and are combined into one which is reeled off on machines. The silk thus obtained is made up into hanks and bundles, and constitutes the raw silk of commerce. _Raw Silk._—The raw silk is very different in appearance and texture to the finished silk that we are accustomed to. It is without lustre, white, yellow, or even, in the case of some Italian silks, orange in color, and quite stiff when handled. These qualities are due to the presence of from 25 to 35 per cent. of gum, which is insoluble in cold water, but is softened by hot water and dissolves readily in a hot soap bath. _Throwing._—The threads of this raw silk are far too fine and delicate to be fit for the weaving processes or even for dyeing. So they are combined into coarser and stronger threads by being “thrown,” a process equivalent to the spinning process of cotton, linen or wool. In throwing, the raw silk fibres are again softened in hot water, and are loosely spun or twisted together while still sticky. Three, four, or five threads of raw silk are usually combined to form one strand of thrown silk, varying, of course, with the quality of the original silk and the objects for which the thrown silk is to be used, when woven. For instance, silk used for filling—“tram,” as it is called in the trade—is usually thicker and softer, and less strong than the warp, or “organzine,” and therefore is usually built up, by the “throwster,” from many threads of less valuable raw silk, loosely twisted, while the organzine, used for warp, is generally of the best and strongest available material, thrown in finer strands out of fewer threads of raw silk, twisted more tightly. It must always be remembered that the skein silk is thrown from very long continuous threads of raw silk, full of gum, whereas spun silk, which is being used more and more every year, is made from short lengths of waste and scrap silk, held together not by gum, but by tight twisting and spinning, just like cotton or linen.