806 



WEAVING. 



WEDGE. 



803 



Concerning the application of the arts of design to weaving, Professor I all or any one of the colours; but the current would pass only 

 Willis, in a report ou the Paris Exhibition of 1855, gives an interesting , through those plates which rest on the one colour represented by the 

 account of the duties of a French functionary called the ' Professeur de strip connected at that moment with the pole of the battery. The 



la Theorie des Fabrications ' : " This is a class of instruction which 

 appears to be peculiar to Lyons, and to the want of which our defi- 

 ciency in that respect may greatly be attributed. Their business is 

 not to teach artistic drawing as a branch of fine art, but to teach the 

 connection of design with the machinery which must be employed to 

 realise it ; to explain the entire construction and management of the 

 looms, the mode of mounting and adjusting them, the different tissues 

 or textures of which they are capable ; the application of these to the 

 respective parts of a given design, either as grounds or as means of 

 bringing out details with the greatest effect, and at the same time with 

 the necessary economy seeing that contrast and variety of textures in 

 the different details of a woven picture occupy the place of the painter's 

 handling in works of fine art. A design may manifestly be exceedingly 



shifting of the band does not hi this case take place with every 

 throw of the shuttle, but after an interval depending on the number 

 of colours. 



Such is Bonelli's electric loom. The inventor states, that two cells 

 of a small Buusen's battery will suffice, consuming one pennyworth of 

 chemicals per day. The cost of the whole apparatus is about 201. An 

 elaborate damask design will sometimes require, on the Jaoquard 

 system 4000 cards and 400 wires, which would cost 2il., and fiva 

 weeks of a man's labour to set up. On the Bonelli system, we are told, 

 the expense would be 61., and the time one week. A Jacquard design 

 has been known to take 20,000 cards, costing 1501., and an amount of 

 labour equal to one whole year of one man's tune ; the figures on tha 

 Bonelli system would be 264. and one month. Several advantages are 



beautiful hi itself as a work of art, but wholly inapplicable to weaving. I claimed for the system : 1. The great facility with which, in a very 

 ^...i;^i ^oto .,,. ,!<,.,; ,,,I,;M, ! ghort time, and with precision, reductions of the design may bo 



obtained on the fabric b^ means of the varying velocity with which the 

 design may be passed under the teeth. 2. That without damaging tha 

 mounting of the loom or the design, fabrics thinner or thicker may bo 

 produced by changing the number of the weft, and making a cor- 

 responding change in the movement of the design. 3. The loom and 

 its mounting remaining unchanged, the design may be changed in a 

 few minutes by the substitution of another metallised paper having a 

 different pattern. 4. The power of getting rid of any part of the 

 design, if required, and of modifying it. The validity of these claims 

 remains for the future to show. 



WEB. [WEAVING.] 



WEDGE, in Mechanics, is a prism of wood or metal whose base is a 

 triangle : ib is employed to remove two objects from one another 

 laterally, or to rend asunder the parts of a body ; an edge which is 



No artist, therefore, can be qualified to make a weaver's design which 

 shall combine in itself the beauty of art, applicable to produce effective 

 results when translated from oil-paint or water-colours into silk or 

 worsted, unless he be familiar with the mechanism of the looms in 

 their infinite variety, with their practical adjustment, and with the 

 characteristic surface-effects of the different tissues. Every designer, 

 in short, should be able to put his own designs into the loom. Accord- 

 ingly, artists, after having studied in the School of Design, at Lyons, 

 put themselves in the next place under the instruction of one of these 

 so-called Professors of the Theory of Fabrics, for six months or more, 

 to learn the application of the design to the machine. This is the 

 system which has enabled the manufacturers of that city to produce 

 the magnificent and beautiful specimens which were displayed in the 

 galleries of the French Exhibition." 



" "i Electric Loom. There is one modern invention in weaving 



of so remarkable a character as to deserve special notice. The theory is j parallel to the geometrical axis of the prism being introduced between 

 Bound, although there may not at present be obtained a mastery over the | the objects, or parts of the body, and the whole wedge being then 



. i. _i j_i _;i_ t ; li L II "o 11:'.. fl i_*~ 1 \ J_; e i i i> . 



mechanical details for carrying it out. M. Bonelli's Electric Loom has 

 been described by Dr. Faraday at the Royal Institution, and by Mr. 

 Le Neve Foster at the Society of Arts. The following is a slight out- 

 line of its origin and nature. In 1844 the Society of Arts prize was 

 given to Mr. Riding for certain improvements in the Jacquard Appa- 

 ratus ; he employed an index-machine, something like Duncan's barrel 

 described in an earlier paragraph, with shifting pegs for changing the 

 patterns, the pegs acting in connection with wires in the apparatus. 

 In later years other improvements were introduced, many of which 

 have been noticed in JACO.UAHD APPARATUS. This subject attracted 

 the attention of M. Bonelli, an Italian Civil Engineer, and Director 

 General of the Sardinian telegraphs. He employed a long period of 

 time in developing the theory and details of an electric apparatus which 

 might dispense with the cards necessary in the Jacquard looms for 

 weaving figured goods ; and brought his machine to England in 1869. 

 Bonelli's apparatus will suit any existing looms. It consists principally 

 of an endless band of paper covered with tinfoil. The design or pattern 

 is painted on the tinfoil with a brush and black varnish. The band 

 panes under a aeries of thin metal teeth, all in connection with a 

 galvanic battery. Whenever the foil touches a tooth a current passes 

 through it, and thence through coils of wire surrounding small bars of 

 soft iron, making them temporary magnets ; but whenever the varnish 

 touches a tooth, no such current is produced. Numerous small rods 

 are placed opposite the ends of the small bar magnets; they pass 

 horizontally to and fro, through a plate in front of a uioveable frame. 

 When any of the bars arc actively magnetic, they retain or attract the 

 rods when in contact with them. When the frame is swung or moved 

 so as to bring the rods in contact with the bars, some are drawn a 

 little distance through the holes in the plate, while the others are not 

 EO affected : according as the particular bars are at that moment in a 

 magnetic state or not. The rods are like pistons, for each exactly fits 

 one hole without tightness ; and thus it happens that, when the frame 

 recedes, some of the holes are open, while others are filled with the 

 rods. The plate acts the part of a Jacquard card ; each movement of 

 the frame opens a distinct series of holes, and thus changes the 

 pattern. A treadle moves the frame, at each throw of the shuttle. 

 When the design is to be in several colours, it is in like manner 

 painted on the tinfoil ; but each separate colour, by removing a very 

 thin strip of foil at the margin, is insulated from its neigh bouring 

 Colour. All the pieces of foil thus insulated, each representing one 

 colour or shade, are connected by small strips of tinfoil, which pierce 

 through the paper and are fastened at the back, whence they are con- 

 ducted to another strip of tinfoil which runs along the edge of the 

 band : there being as many such strips of tinfoil as there are colours. 

 Thus each special colour of the design, in all its parts, is connected by 

 * conductor with its own separate strip of tinfoil. By bringing the 

 wire from the galvanic battery successively into contact with the 

 several strips, a current of electricity may be made to pass in succession 

 through the several |rts of the design representing the several 

 colours. Thus, assuming four colours ; there would be four strips of 

 tinfoil running the length of the band, insulated one from another, 

 each in connection with its own peculiar colour only. At any given 

 moment, thin plates of metal resting on the design would touch it in a 

 line which, as it passes over the width of the design, would run through 



driven forward by a percussive force, as the stroke of a hammer. The 

 nature of percussive force, and of the resistance which a yielding 

 material opposes to the motion of the wedge being, however, imper- 

 fectly known, it is usual to consider the motive-power and the 

 resistance as simple pressures, or weights, in estimating the conditions 

 of equilibrium when a wedge is employed as a machine. 



Let ABO represent the section of a wedge perpendicularly to the 

 mathematical axis ; and for simplicity, suppose this section to be an 



isosceles triangle. The plane passing though AB, perpendicular to 

 ABC and to the paper, is called the head or back of the wedge : the 

 planes passing through AC and BO perpendicular to the paper are 

 called the sides ; and their line of section, passing through o, is called 

 the edge. 



The motive-power is applied to the head of the wedge ; and may be 

 supposed to act in the direction MO perpendicularly to that plane, and 

 passing through c in the edge. Let the material which is to be rent 

 asunder be in contact with the sides of the wedge in lines passing 

 through a and 6 perpendicularly to the paper ; and let the two parts 

 yield as if they were capable of turning about some point c in the 

 direction of M o, produced if necessary : then it is evident tliat the effect 

 of the wedge will be the same as if a section of the latter, perpendicularly 

 to the axis, were abc. Imagine ad, bd to be drawn perpendicularly to 

 ac and be ; then those lines will meet at a certain point, as d, in the 

 line MC: imagine also the parallelogram adbo of forces to be con- 

 structed ; then do or ZdN will represent the motive force, and da or 

 db the pressure which that force exerts at o or 6 perpendicularly to 

 ac and be. Let s represent the motive force, and u the pressure at 

 a or 4 , then, in a state of equilibrium, the latter will represent the 

 reaction of the material in the direction ad or bd ; and we have 



p : B : : 2<?N : da. 



