NATURAL PHILOSOPHY. 



the weft, as there must be as many cards as there are wefts or cross-threads 

 in a pattern. Lastly, all the cards must be sewn together in the order of 

 their succession. AVe have already shown how in the " Jacquard " these 

 pierced cards act on the pins of the loom, and determine the raising of the 

 threads of the warp or basis of the material beneath. M. Bonelli's looms 

 instantly accomplish all this work we have been describing, with an exacti- 

 tude that could never be obtained from " the cards," which, as our readers 

 will easily understand, \vere almost incapable of producing a very complex 

 pattern. It is by passing the thread of the weft over or under the thread of 

 the warp that the design, either in one or many colors, is produced. The 

 design in M. Bonelli's plan is traced on a sheet of tinfoil, the pattern remain- 

 ing in bright metal, while all the rest is painted over with a non-conducting 

 varnish. The metal pattern thus becomes the conductor of the electricity ; 

 the varnished portions do not. This thin sheet of tinfoil is placed on a roller, 

 which revolves it by very slow degrees, with a uniform movement, iinder a 

 metallic comb. This comb contains teeth equal in number to the pins of a 

 Jacquard loom, from four hundred to six hundred, each of which is 

 most carefully insulated from the next, and each connected by a fine wire 

 with a small electro-magnet or bobbin. A wire from a small Bunsen pile is 

 connected with this comb and electro-magnets, the other wire with the tinfoil 

 design. When by the ordinary movement of the Jacquard loom, effected by 

 the foot of the workman pressing the treadles, the loom moves, the metallic 

 comb lowers itself, and comes in contact with the tinfoil sheet of the design. 

 The teeth of the comb touching on the varnished portions, of course, stop the 

 passage of an electric current to the bars with which they communicate, and 

 which, in fact, therefore remain mere bobbins. Ail those, on the contrary, 

 which touch the metallic parts of the sheet the design, in fact allow the 

 current to pass to the electro-magnets, which instantly become active, and 

 capable of attracting little horizontal bars of iron, which are arranged with 

 their points towards the magnets in a frame common to them all. Those 

 magnets, therefore, which are active, at once attract and retain the bars as the 

 frame, all by a simple movement, in a second, moves a little back and lowers, 

 and thus the threads of the warp below, which are attached to crochet- 

 needles hanging on to the magnetized bars, are raised, and the shuttle with 

 the weft of the pattern-thread passes in between them. 



There is a little mechanical contrivance employed to give solidity to the 

 arrangement of the bars, a solidity which is necessary, as the magnetized 

 bars have to act upon the needles of the loom, and keep them and their 

 threads suspended. Such are the chief features of this electro-magnetic 

 weaving machine, which, apart from its scientific merits, contains, in addi- 

 tion, some most admirable mechanical contrivances. Such, for instance, is 

 the ingenious means by which the design-sheet moves with a speed variable 

 at will, and either backwards or forwards, and the addition of a little brush 

 to clean the comb. This last, at each motion of the loom, sweeps across all 

 its teeth, to prevent the injurious action of the dust, which, falling upon the 

 surface, would soon interfere with the action of the electric fluid. The loom 

 which we have now described is only applicable to stutfs of two colors ; that 

 is to say, of one color upon one general ground. But a loom capable of 

 weaving stuffs of six, eight, or ten colors, only differs by the addition of 

 a most simple piece of mechanism, thus : Each of the different colors is 

 insulated from the other, and along them, on the pattern, the pole of the bat- 



