WEAVING BY ELECTRICITY 



1117 



pistons to be carried back, their heads remaining outside the plate and in front of it. 

 At this moment, the plate, by means of an inclined plane beneath it, is lowered 

 slightly, thus preventing the heads of the pistons passing through the holes, by the 

 edges of which they are stopped, so as to push against the needles of the Jacquard ; 



2110 



on the other hand, the heads of the pistons which have passed within and to the back 

 of the plate, leave the corresponding holes of the plate free, and the needles of the 

 Jacquard which are opposite to them are allowed to enter. 



The electro-magnets are put into circuit in the following manner: One of the ends 

 of the wire forming the coil of each of the magnets is joined to one common wire in 

 connection with one of the poles of a galvanic battery. The other end of the coil- 

 wire of each magnet is attached to a thin metallic plate, m, having a point at its lower 

 extremity. All these thin metallic plates are placed side by side, with an insulating 

 material between them, formed like the teetli of a comb, n n. At a given time, these 

 thin plates rest with their lower extremities on the sheet bearing the design p, which, 

 in the form of an endless band, is wrapped round and hangs upon the cylinder, Q, and 

 according as the thin metal-plate rests on a metallised or on a non-conducting portion 

 of the design, the corresponding electro-magnet is or is not magnetised, and its corre- 

 sponding piston does not or does press against the needle of the Jacquard. The wire 

 from the other pole of the battery of course communicates with the band bearing the 

 design, by being attached to a piece of metal, which lies in constant contact with the 

 metallic edge of the band. At B is a contact-breaker, which is put in motion by the 

 movement of the frame. Besides this, by means of a mechanical arrangement con- 

 nected with the treddle, which raises or depresses the griff frame, the band bearing 

 the design is carried forward at each stroke, and the rapidity with which it is made 

 to travel can readily be regulated, by moans of gearing, at the will of the workman. 

 By regulating the speed of the band, and by the use of thicker or thinner weft, an 

 alteration in the character of the woven material may be made, whilst the same 

 design is produced, though in a finer or coarser material. 



Such are the arrangements by which the loom will produce a damask pattern, or 

 one arising from the use of two colours, one in the warp, and the other in the weft. 

 The method adopted by M. Bonelli for producing a pattern where several colours are 

 required will now be explained. 



The design is prepared on the metallised paper, so that the coloured parts are 



