%'8 COTTON-SPINN1KG 



a full lap is to be removed, and replaced by an empty one. m, at the top, is the 

 commencement of the pipe which leads to the suction fan, or ventilator. 



It is to be observed that different kinds of cotton require different kinds of treat- 

 ment in the opening and scutching operations. Some scutchers have only one boater, 

 others two or oven three. Sometimes the opener has two beaters, so that altogether 

 the cotton is made to pass through as many as five beaters. As a rule, however, it is 

 well to boat or tear it as little as is possible, having in view the main purpose of this 

 operation, viz. to loosen and to cleanse it from the more palpable impurities. For not 

 only does the staple suffer from repeated strain, but the longer stapled cottons are liable 

 occasionally to get knotted or 'nopped,' and thus to introduce almost irreparable 

 mischief into the subsequent operations. 



The operations of opening and scutching are exposed to frequent risks of fire. 

 Pieces of stone, of flint, of metal, and even boxes of lucifor matches are not unfro- 

 quently found in cotton. Whenever these pass into the machines and are struck by the 

 beaters, there is imminent danger of fire. Hence the rooms in which these operations 

 are carried on are almost invariably fireproof, and are built quite separate from the rest 

 of the factory, communicating with it only by a covered fireproof gangway. 



The cotton thus opened and to a certain extent cleaned is yet, however, in a very 

 unfit state for being spun into yarn. The fibres, on examination, will be found 

 mingled in a confused mass, and whether straight, or curled, or folded, lying in every 

 possible direction. Moreover, it will be seen that there are amongst the longer fibres 

 many so short as to bo unfit for combination with them, some also will be knotted, or 

 ' neppy,' and added to these imperfections many ' moats,' small pieces broken off the 

 pod or the seed of the cotton, besides other forms of finer impurity. For the purpose 

 of separating the useful fibres from the foreign accompaniments and laying them in 

 parallel order, we have the operation of Carding. The essential part of this operation 

 may be described as the mutual action of two opposite surfaces, which are studded 

 thick with oblique-angled hooks. The wires of which these hooks are made must be 

 very hard drawn in order to render them stiff and elastic. The middle part of the 

 figures shows one of the staples or double teeth, the structure of which has been partly 

 explained under CAED. Suppose a, fig. 550, to bo a piece of a card fillet, and b to be 



550 



another piece, cnch being mado fast with pins to a board; the teeth of these two cards 

 ire set in opposite directions-, but are very near together, and parallel. Now suppose 

 a flock or tuft of cotton placed between two such bristling surfaces. Let a be moved 

 in the direction of its arrow, and let b be moved in the opposite direction, or even let 

 it remain at rest. The filaments of cotton will bo laid hold of by each set of teeth, 

 when their surfaces are thus drawn over each other ; the teeth of a will pull them in 

 a forward direction, while thoso of b will tend to retain them, or to pull them back- 

 wards. The loops or doublings will, by both movements, be opened or drawn out, so 

 that the tangled fibres will be converted into rows of parallel filaments, lying alongside 

 or before each other. Each tooth will secure to itself one or more of them, and by tho 

 friction of its sides as well as the hooks of its points, will draw them to their utmost 

 elongation. Though one stroke of the opposite cards be inadequate to produce this 

 equable arrangement, yet many repeated strokes must infallibly accomplish the end in 

 'view, of laying tho fibres parallel. 



Let us suppose this end effected, and that all the fibres have been transferred to the 

 card a, a transverse stroke of b will draw over to it a certain number of them, and in- 

 deed at each stroke there will be a now partition between the two cards, with increased 

 parallelism, but still each card will retain a great deal of tho cotton. To make one 

 card strip another, the teeth of one of them must be placed in a reverse position, as 

 shown in fig. 551. If a be now drawn in the direction of its arrow along the face of b, 

 it will inevitably comb out all, or almost all, the filaments from it, since the hooks of 

 h have, in this position, no po\ver of retaining them. Even the doubled fibres or 

 loops will slip over the sloping point of b, in obedience to the traction of a. By consi- 

 doring these two relative positions of the cards, which take place in hand cards simply 

 by reversing one of them, any person will be able to understand the play of a 

 tjrlinder card against its flat top, or ngainst another cylinder card, the respective teeth 



