CHAPTER XII. SILK MACHINERY. Bobbin Mechanism. The plate annexed represents the series of changes from the formation of the egg to the death of the silk moth. We shall explain it with reference to the figures that are marked upon it. 1. The egg, or the development and birth of the silk-caterpillar, 2. The silk-worms, during the first age, till their first moulting. 3. Rearing of the worms in the second age. 4. The worms in their third age. 5. Rearing of the silk-worm in the fourth age. 6. The rearing of the silk-worms during the fifth age, until the completion of the cocoon. 7. A species of silk-worm of a dark gray colour, with singular marks. 8. The cocoons. 9. Two open cocoons, or cocoons with their grubs. The upper one contains only the shell of a developed chrysalis, but in the lower is seen the immature chrysalis, with the skin of the late moth. 10. A cocoon, from which the butterfly is near emerging. 11. A cocoon from which the butterfly has already escaped. 12. Two butterflies in the act of coupling. 13. The female moth laying eggs. 14. Raw silk, of a yellow or white colour. 15. Here is represented the excremental substance of the silkworm, in its first and last age. The silk-worm is a robust little animal, and its organisation is simple; but the rearing of it is often so defective, that, notwithstanding its sound constitution, it frequently perishes from the ill management it experiences in its rearing. It must not be concealed, that some antagonists of this industry have maintained that it is injurious to the human constitution. But this is a mere prejudice, or a vain pretence. No human being has yet suffered, bodily, from this cause. Silk Engine or Swift The machinery of the silk filature, from Dr. Ure.-These filatures are very simple; but the throwing-mills, for doubling and twisting silk, are most elaborate constructions. Ever since they were remodeled by Fairbairn, and upon the cotton-throstle plan, they are incomparably superior in convenience, precision and speed of performance, to what they formerly were in England, and still are in other parts of Europe. When these mechanicians took the silk-mill in hand, the spindles moved at the rate of only 1,200 revolutions per minute: they forthwith raised it to 3,000,-a velocity since increased to 4,500 by Ritson, a cotton mill mechanic, in whose favour they resigned this branch of engineering. The representations inserted are parts of a complete series of drawings made, under my inspection, from the latest and most improved silk-throwing machinery erected by him. The first operation which raw silk undergoes in the factory, is its transfer, from skeins upon bobbins, in diagonal lines; so that the ends of the threads may be readily found, in case of breakage. The bobbins are wooden cylinders of such thickness as not to injure the filaments by sudden flexure, which smaller cylinders would do, and to be able to receive a considerable length of thread without materially increasing their diameters; and, of course, their surface velocity in revolving. The winding machine, called the engine, consists of a long wooden table, for. laying out the skeins upon. These are called swifts, because, though they turn slowly round with the revolving bobbins, yet they do their work quickly, compared with handwinding machines. Doubling Engine.-In the doubling of silk, where two or three threads are wound, parallel together, upon one bobbin, an ingenious contrivance is employed to stop the winding whenever one of the threads happens to break. The machine for twisting the single threads of silk, either before the doubling or after the doubling, is called the spinning-mill, sometimes also the throwing-mill; though the latter term often End view of Fairbairn's and Lillie's improved Silk Spinning Mill. includes all the departments of a silk-mill. The section above, of this apparatus, shows four equal working lines, namely, two on each side of the frame, one tier being over the other. In some spinning mills there are three tiers, but the uppermost is a little troublesome to manage, as it requires the attendant to mount a stool or steps. Silk undergoes certain preparations. The hanks of the raw silk are soaked in tepid soap-water in a tub; but the bobbins of the spun silk are steamed by inclosing a basket full of them within a wooden steam case, for about ten minutes. The bobbins are then removed into a cistern of warm water, from which they are taken to the doubling frame. It is probable that the power-loom will be applied to the weaving of fancy, as well as plain goods; which will give a great impulsion to the silk trade of England. Sharp & Roberts will readily furnish the requisite machinery for producing any wished-for design, however complicated. What is to prevent its introduction into America? In silk establishments, the |