SILK MANUFACTURE 



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G (fig. 1768) is a long ruler or bar of wood, which is supported upon every eighth or 

 twelfth leg B, B. (The figure being, for convenience of the page, contracted in length, 

 shows it at every sixth leg.) To the edge of that bar the smooth glass-rods k, are 



1771 



1770 



B 



fl 



made fast, over which the threads glide from the swifts, in their way to the bobbins. 

 H (fig. 1770) is the guide-bar, which has a slow traverse or seesaw motion, sliding in 

 slots at the top of the legs B, -where they support the bars o. Upon the guide-bar H, 

 the guide-pieces I, I, are made fast. These consist of two narrow, thin, upright plates 

 of iron, placed endwise together, their contiguous edges being smooth, parallel, and 

 capable of approximation to any degree by a screw, so as to increase or diminish at 

 pleasure the ordinary width of the vertical slit that separates them. Through this 

 slit the silk thread must pass, and, if rough or knotty, will be either cleaned or 

 broken ; in the latter case, it is neatly mended by the attendant girl. 



The motions of the various parts of the engine are given as follows : Upon the end 

 of the machine, represented in fig. 1767, there are attached to the shafts E (fig. 1768), 

 the bevel-wheels 1 and 2, which are set in motion by the bevel-wheels 3 and 4, respec- 

 tively. These latter wheels are fixed upon the shaft m,fig. 1767 ; in is moved by the 

 main steam-shaft which runs parallel to it, and at the same height through the length 

 of the engine apartment, so as to drive the whole range of the machines. 5 is a loose 

 wheel or pulley upon the shaft m, -working in gear -with a wheel upon the steam-shaft, 

 and which may be connected by the clutch n, through the hand-lever or gearing-rod o 

 (figs. 1767 and 1768), when the engine is to be set at work. 6 is a spur-wheel upon 

 the shaft.m, by which the stud-wheel 7, is driven, in order to give the traverse motion 

 to the guide-bar H. This wheel is represented, with its appendages, in double size, 

 figs. 1772 and 1773, with its boss upon a stud p, secured to the bracket q. In an 

 eccentric hole of the same boss, another stud r, revolves, upon which the little wheel s, 

 is fixed. This wheel s is in gear with a pinion cut upon the end of the fixed stud p ; 

 and upon it is screwed the little crank t, whose collar is connected by two rods u (figs. 

 1767 and 1768), to a cross-piece v, which 



L 1773 



unites the two arms w, that are fixed upon 

 the guide-bar H, on both sides of the 

 machine. By the revolution of wheel 7, 

 the wheel s will cause the pinion of the 

 fixed stud p to turn round. If that wheel 

 bear to the pinion the proportion of 4 to 1, 

 then the wheel s will make, at each revo- 

 lution of the wheel 7, one-fourth of a re- 

 volution ; whereby the crank t will also 

 rotate 'through one-fourth of a turn, so as 

 to be brought nearer to the centre of the 

 stud, and to draw the guide-bar so much less to one side of its mean position. At the 

 next revolution of wheel 7, the crank t will move through another quadrant, and come 

 still nearer to the central position, drawing the guide-bars still less aside, and there- 

 fore causing the bobbins to wind on more thread in their middle than towards their 

 ends. The contrary effect would ensue, were the guide-bars moved by a single or 

 simple crank. After four revolutions of the wheel 7, the crank t will stand once more 

 as shown' in fig. 1774, having moved the bar H through the whole extent of its 

 traverse. The bobbins, when filled, have the appearance represented in fig. 1774; 

 the thread having been laid on them all the time in diagonal lines, so as never to 

 coincide with each other. 



Doubling is the next operation of the silk-throwster. In this process, the threads of 

 two or three of the bobbins, filled as above, are wound together in contact upon a 

 single bobbin. An ingenious device is here employed to stop the winding-on the 



