4 JACQUARD-LOOM 



Fig. 1293 represents the plan of the upper row of horizontal needles. Fig. 1294 is 

 a fragment of the endless chain, formed with perforated cards, which are made to 

 circulate or travel by the rotation of the shaft D. In this movement, each of the 

 perforated cards, whose position, form, and number are determined by the operation 



1293 



1294 



g o 



of tying-up of the warp, comes to be applied in succession against the four faces of the 

 square axis or drum, leaving open the corresponding holes, and covering those upon 

 the face of the axis which have no corresponding holes upon the card. 



Now let us suppose that the press B is let down into the vertical position shown in 

 Jig. 1289 ; then the card applied against the left face of the axis, leaves at rest or 

 untouched the whole of the horizontal spindles (skewers), whose ends correspond to 

 these holes, but pushes back those which are opposite to the unpierced part of the 

 card ; thereby the corresponding upright skewers, 3, 5, 6, and 8, for example, pushed 

 out of the perpendicular, unhook themselves from above the bars of the claw, and 

 remain in their place, when this claw comes to be raised by means of the lever o ; and 

 the skewers 1, 2, 4, and 7, which have remained hooked on, are raised along with the 

 warp threads attached to them. Then by the passage across of a shot of the colour, 

 as well as a shot of the common weft, and a stroke of the lay after shedding the warp 

 and lowering the press B, an element or point in the pattern is completed. 



The following card, brought round by a quarter revolution of the axis, finds all the 

 needles in their first position, and as it is necessarily perforated differently from the 

 preceding card, it will lift another series of warp threads ; and thus in succession for 

 all the other cards, which compose a complete system of a figured pattern. 



This machine, complicated in appearance, and which requires some pains to be un- 

 derstood, acts however in a very simple manner. Its whole play is dependent upon the 

 movement of the lever o, which the weaver himself causes to rise and fall, by means 

 of a peculiar pedal ; BO that without the aid of any person, after the piece is properly 

 read in and mounted, he can execute the most complex patterns as easily as he could 

 weave plain goods ; only attending to the order of his weft yarns, when these happen 

 to be of different colours. 



If some warp yarns should happen to break without the weaver observing them, or 

 should he mistake his coloured shuttle yarns, which would so far disfigure the pattern, 

 he must undo his work. For this purpose, he makes use of the lower hooked lever/', 

 whose purpose is to make the chain of the card go backwards, while working the loom 

 as usual, withdrawing at each stroke the shot both of the ground and of the figure. 

 The weaver is the more subject to make mistakes, as the figured side of the web is 

 downwards, and it is only with the aid of a bit of looking-glass that he takes a peep of 

 his work from time to time. The upper surface exhibits merely loose threads in dif- 

 ferent points, according as the pattern requires them to lie upon the one side or the 

 other. 



Thus it must be evident, that such a number of pasteboards are to be provided and 

 mounted as equal the number of throws of the shuttle between the beginning and end 

 of any figure or design which is to be woven ; the piercing of each pasteboard indi- 

 vidually will depend upon the arrangement of the lifting rods, and their connection 

 with the warp, which is according to the design and option of the workman ; great 

 care must be taken that the holes come exactly opposite to the ends of the needles ; 

 for this purpose two large holes are made at the ends of the pasteboards, which fall 

 upon conical points, by which means they are made to register correctly. 



It will be hence seen, that, according to the length of the figure, so must be the 

 number of pasteboards, which may be readily displaced so as to remount and produce 

 the figure in a few minutes, or remove it, or replace it, or preserve the figure for future 

 use. The machine, of course, will be understood to consist of many sets of the lifting 

 rods and needles, shown in the diagram, as will be perceived by observing the dispo- 

 sition of the holes in the pasteboard ; those holes, in order that they may be accu- 

 rately distributed, are to be pierced from a gauge, so that not the slightest variation 

 shall take place, 



