WEAVING. 



has been gone through; but when this is completed, and a 

 repetitioa of the pattern is wanted, the weaver muft flop 

 and reftore the machine to its oriojinal pofition by pulling a 

 ftring. This appears very eafy, but it diverts his attention ; 

 and if he does not do it at the cxaft moment his pattern 

 may be fpoiled. This defeft was remedied by Mr. Alexan- 

 der Duff, who received a fmall and inadequate premium 

 from the Society of Arts in 1807, probably becaufe they 

 were not aware of its value and importance; but in 1810 

 we find them with a liberahty truly difcouraging to real 

 merit, giving an equal reward to another perfon, for the 

 moft trivial alteration of Duff's machine. The latter ma- 

 chine is alone defcribed in their Tranfaftions ; fee vol. xxviii. 



Mr. Duff'' s Draw-Boy. — Fig. 4. Plate II. Weaving, is a 

 plan of this machine, and J?f. 2. a perfpeftive view. It is 

 fixed at the fide of a draw-loom, in the fame place as a draw- 

 boy would ftand, and H Ihew the cords which are to draw the 

 harnefs. The fame letters are ufed in both figures. A A 

 is a fquare wooden axis, mounted fo as to turn backwards 

 and forwards in the frame B B, on points or centres of mo- 

 tion. At one end of it a pulley D is fixed, to receive a line 

 a a fattened to it at the higheft point, by means of which 

 the axis receives motion from the two treadles of the loom, 

 one of the treadles being attached to one end of the line, and 

 the other to the oppofite end of it. E E are two rails of 

 wood, fixed acrofs the frame parallel to the axis; andf? 

 are two brafs plates fcrewed to the rails, and pierced with a 

 great number of holes to receive as many cords. Each 

 cord is tied by one end to a central rail F of the frame be- 

 neath the axis ; and after palling through one of the holes 

 in the above plate e, and turning over a round wooden rod 

 G, has a lead weight fufpended to the other end of it. 

 Thefe weights are (hewn at h b. The rods G G are fuf- 

 pended by firings at their ends from the ceiling of the room. 

 To each of the above cords another is tied juft before it 

 pafTes over G. Thefe are reprefented by H, and hang 

 loofely. The upper ends of thefe cords are tied to hori- 

 zontal cords extended acrofs the ceiling of the room, and 

 made faft to the ceihng at one end; the other ends pafs over 

 pulleys fituated at the top of the loom, in a frame called 

 the table of mullets, and the harnefs or heddles are fuf- 

 pended by them. 



By this arrangement it will be feen, that when any one of 

 the cords fattened at F is pulled down, it muft draw one of 

 the ttrings H, and raife fuch an arrangement of the har- 

 nefs or heddles as is proper to produce the figure which is 

 to be woven. The weight b draws the cord fo as to keep it 

 ftraight ; all that is therefore neceffary is to draw down the 

 cords at F one at a time, but to take a different one each 

 time, and thus raife a different feries of the heddles each 

 time ; this is the bufinefs of the machine, and which it ac- 

 compUtties in the foliowang manner. 



The bar, or axis, A A, has an iron femicircle, d, 

 grooved like a pulley, and each of its ends divided, fo as 

 to form a cleft-hook or claw. 



Each of the ftrings made faft at F has a large knot tied 

 jn it, juft beneath where it paffes through the brafs plate e e, 

 and which knot ftops the farther afcent of the cord, in con- 

 fequence of the pull of the weight b. Now when the axis 

 A vibrates backwards and forwards by the treadles of the 

 loom, as before mentioned, the hook of the femicircle d 

 feizes the knot of one of the cords F, and draws down that 

 cord, and raifes the heddles belonging to it. The weaver 

 throws the (huttle, and then returns the treadles, and the 

 axis A with the femicircle returns back again, and allows 

 the cord F to take its original pofition. When the femi- 

 circle d inclines over to the other fide, its oppofite hook 



takes hold of the cord F, which is next to the one op- 

 pofite to that which it juft quitted ; it draws down this 

 cord, and the weaver again throws his fhuttle, then re- 

 turns the femicircle to the oppofite fide, and it will take 

 the cord next to the oppofite one, and fo on ; fo that tlie 

 femicircle will in fucceffion take every alternate cord in each 

 of the rows c e, and leave every other. 



This is effefted by the femicircle Aiding along its axis A 

 every time, by means of two wooden racks, h and /, in 

 the plan, which are let into grooves in the axis A{; thefe 

 racks have teeth like faws, but inclined in contrary direc- 

 tions. The rackj move backwards and forwards in their 

 grooves, the extent of a tooth at each vibration of the axis, j 

 by the aftion of two circular inclined planes of iron faftened I 

 to the frame at L M, again ft which the ends of the racks 

 are thrown by fpiral fprings concealed beneath each rack. 

 The femicircle is fixed on a box or carriage N, which fiides J 

 upon the axis A, and has two clicks upon it ; one at /, I 

 which falls into the. teeth of the rack h ; the other at m 

 for the rack / : n is a roller fixed over the box, and connefted 

 with the two clicks / and m, by threads wound in oppofite 

 direftions ; fothat one click is always raifed up, and difengaged 

 from its rack, while the other is in aftion. O is a piece of wire 

 fixed to the frame, fo as to intercept a fmall wire projefting 

 from the roller when the axis is inclined, and turn the roller 

 a fmall qaanlity ; P is another wire for the fame purpofe, 

 but fixed to a crofs bar, Q, which is moveable, and can be 

 faftened at any required place, farther or nearer from the 

 end of the axis. Suppofe the roller n to be in fuch a pofi- 

 tion that the click m is down, and / drawn up, the aftion 

 will be as follows : the femicircle firft inclines to the direftion 

 oi Jig- 2., its hook taking down one ftring ; during this mo- 

 tion the end of the rack i comes to the inclined part of the 

 circular inclined plane M, and moves by its fpring towards 

 D, the fpace of one tooth, which the click m falls into. On 

 the return of the axis, the rack i is thruft back, and the box 

 N and femicircle with it towards L, caufing the hook to take 

 the next oppofite ftring : in this manner it proceeds, advan- 

 cing a tooth each vibration, till it gets to the end of its courfe ; 

 the tail of the roller n then ftrikes againft the pin P, and turns 

 the roller over, raifes the click m, and lets down the other, /, 

 into the teeth of the rack i ; this was all the time moving 

 in a contrary direction to i, by its inchned plane L, but had 

 no aftion, as its click / was drawn up ; this being let down, 

 the femicircle is moved back, a tooth at a time, towards M, 

 until it meets O, which upfets the roller n, and fends the 

 femicircle back again. 



Tiueeled Silks. — In weaving very fine filk tweels, fuch as 

 thofe of fixteen leafes, the number of threads required to 

 be drawn through each interval of the reed is fo great, that 

 if they were woven with a fingle reed, the threads would 

 obftruft each other in rifing and finking, and the ftied, or 

 opening of the divided warp, would not be fufiiciently open 

 to allow the ftiuttle a free paffage. To avoid this inconve- 

 nience, other reeds are placed behind that which ftrikes up 

 the weft ; and the warp-threads are fo difpofed, that thofe 

 which pafs through the fame interval in the firft reed>are di- 

 vided in pafFing through the fecond, and again in pafling 

 through the third. By thefe means the obftruftion, if not 

 entirely removed, is greatly leffened. 



In the weanng of plain thick woollen cloths, to prevent 

 obftruftions of this kind arifing from the clofenefs and rough- 

 nefs of the threads, only one-fourth of the warp is funk and 

 raifed by one treadle, and a fecond is preffed down to com- 

 plete the ftied between the times when every {hot of weft is 

 thrown acrofs. 



Double Cloth is compofed of two web«, each of which 



confifts 



