Chapter C: D E F are the four printing cylinders, named in the order of their (13)

The second Blowing machine is usually called a _lap_ machine, because, after blowing and scutching the cotton, as above described, it eventually coils the fleece upon a wooden roller at the delivering end of the apparatus. It is sometimes also called a _spreading machine_. A section of it is shown in _fig._ 319. The breadth of this machine is about 3 feet as the lap formed is prepared for the usual breadth of the breaker cards, namely 3 feet. Where the cards are only 18 inches broad, the lap machine is also made of the same breadth. In the figure we see the feed-cloth, the scutching barrel, the squirrel suction, and spreading cage, and the rollers for coiling up the lap. The lever shown below is for removing the pressure weight from the axis of the lap rollers, when a full one 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. The thickness of the lap in this machine must be nicely regulated, as it determines, in a great measure, the grist of the card ends, and even the rovings. In 12 hours such a lap machine will prepare 650 pounds of cotton.

_Fig._ 320. is the first scutching machine, now never seen except in the oldest factories. A B is the feed cloth; G H and M N are the two scutcher frames.

_Carding_ is the next operation in a cotton factory. Cards are destined to disentangle the individual filaments from each other, and to lay them lengthwise, instead of being doubled up and convoluted, as they usually are in leaving the blowing and lap machines. Carding consists in 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 CARD. Suppose _a_, _fig._ 321. to be a piece of a card fillet, and _b_ to be another piece, each being made fast with pins to a board; the teeth of these two cards are 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. Every filament of the cotton will be 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 those of _b_ will tend to retain them, or to pull them backwards. The loops or doublings will, by both movements, be opened or drawn out, so that the flocks 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 the 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 the 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 indeed at each stroke there will be a new partition between the two cards, with increased parallelism, but still each card will retain a great deal of the cotton. To make one card strip another, the teeth of one of them must be placed in a reverse position, as shown in _fig._ 322.

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 _b_ have, in this position, no power 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 considering 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 cylinder card against its flat top, or against another cylinder card, the respective teeth being in what we may call the teazing position of _fig._ 321.; and also the play of a cylinder card against the doffer cylinder, in what may be called the stripping position of _fig._ 322.

Cylinder cards, so essential to the continuity and dispatch of cotton factory labour, were the ingenious invention of Lewis Paul of Northampton, but were greatly improved and brought into nearly their present operative state by Sir Richard Arkwright. A carding engine consists of one or more cylinders, covered with card-leather (sometimes called card cloth), and a set of plane surfaces similarly covered, made to work against each other, but so that their points do not come into absolute contact. Some cards consist entirely of cylinders, the central main cylinder being surrounded by a series of smaller ones called urchins or squirrels. These are used solely for preparing the coarser stapled cotton, and sheep’s wool for the wool spinner.

_Fig._ 323. represents a card of excellent construction, which may be called a _breaker_ and _finisher_, as it is capable of working up the fleece roll of the lapping machine directly into a card-end or riband fit for the drawing machine. In fine spinning mills there are always, however, two cards; one coarser, called a breaker, which turns off the cotton in a broad fleece of extreme thinness, which is lapped round a cylinder; and constitutes the material presented to the finisher card, which has teeth of a finer construction.

_a_ is one of the two upright slots, which are fixed at each side of the engine for receiving the iron gudgeons of the wooden cylinders round which the fleece of the lapping machine is rolled. The circumference of this coil rests upon a roller _b_, which is made to turn slowly in such a direction as to aid the unfolding of the lap by the fluted cylinders _e_. The lap proceeds along the table seen beneath the letter _c_, in its progress to the fluted rollers, which are an inch and one-sixth in diameter, and have 28 flutings in their circumference. _g_ is a weight which hangs upon the axis of the upper roller, and causes it to press upon the under one: _f_ is the main card drum; _g g g_, the arch formed by the flat top cards; _h_, the small card cylinder for stripping off the cotton, and therefore called the doffer, as we have said; _i_, the doffer-knife or comb for stripping the fleecy web from the doffer; _k l q m_, the lever mechanism for moving these parts. At _d_ there is a door for permitting the tenter to have access to the interior of the engine, and to remove whatever dirt, &c. may happen to fall into it. In _fig._ 324. we see the manner of fixing the flat tops _g g_ over the drum; and for making the matter clearer, three of the tops are removed. Upon the arched cast-iron side of the frame, a row of strong iron pins _k_ are made fast in the middle line; and each top piece has, at each of its ends, a hole, which fits down upon two such opposite pins. _l l_ are screws whose heads serve as supports to the tops, by coming into contact with the bottom of the holes, which are not of course bored through the wood of the tops. By turning the heads of these screws a little the one way or the other, the pins may be lengthened or shortened in any degree, so as to set the tops very truly in adjustment with the drum teeth revolving beneath them, _h´_ is the small runner or urchin, and _i´_ the large runner; both of which are spirally covered from end to end with narrow card fillets, in the same manner as the doffer. The main drum is on the contrary covered with card cloth, in strips laid on parallel to its axis, with interjacent parallel smooth leather borders. The teeth of these several cards are set as represented in the figure, and their cylinders revolve as the arrows indicate. The runners as well as the doffer cylinder may be set nearer to or farther from the drum _f_; but the screws intended for this adjustment are omitted in the drawings, to avoid confusion of the lines.

The card-end or fleece taken off the doffer _h_ by the crank and comb mechanism _i k m_, passes through the tin plate or brass funnel _n_, _fig._ 323., whereby it is hemmed in and contracted into a riband, which is then passed through between a pair of drawing rollers _o_. It is next received by the rollers _u v_, which carry it off with equable velocity, and let it fall into the tin cans placed below, or conduct it over a friction pulley, to be wound along with many other card-ends upon a lap roller or large bobbin. The latter mechanism is not shown in this figure. A sloping curved tin or brass plate, channelled or ridged along its surface, conducts the card ribands separately; there are two smooth iron rollers for condensing the several ribands, and a wooden pin round which the ribands are lapped, resting between two leather-covered rollers, one of which receives motion from mill geering, and imparts it by friction to the lap roller over it. The iron ends of the lap roller lie in upright slots, which allow them freedom to rise as the roller gets filled with fleece.

The two pairs of rollers at _o_, effect the extension of the card-end, and reduce its size. The under rollers are made of iron and fluted; the upper ones are also made of iron, but they are covered with a coat of leather, nicely glued on over a coat of flannel, which two coats render them both smooth and elastic. Two weights, _w_, press the upper cylinders steadily down upon the under ones. Between the first and second pair there is a certain interval, which should be proportioned to the length of the cotton staple. The second, or that furthest from the funnel, revolves with greater velocity than the first, and therefore turns out a greater length of riband than it receives from its fellow; the consequence is a corresponding extension of the riband in the interval between the two pairs of rollers.

The motions of the several parts of the engine are effected in the following way. The band, _p p_, _fig._ 324., which comes down from the pulley upon the main shaft near the ceiling of the work-room, drives, by means of the pulley _q_, the drum _f_, _fig._ 323., with a velocity of from 120 to 140 revolutions in a minute. From another pulley _r_, on the axis of the drum, the axis of _t_ is driven by the band _s_ working round the pulley _t_ on its end. This shaft drives the crank and lever mechanism of the stripper knife _i_. A third pulley of the same size as _r_ is fixed just within the frame to the other end of the drum, and from it a crossed or close band _r´_ goes to a pulley upon the small runner _h´_, to give this its rapid rotation. Upon the opposite end of the engine in _fig._ 323., these wheels and pulleys are marked with dotted lines. Here we may observe, first, a pulley _y_ upon the drum, and a pulley _a´_, which receives motion from it by means of the band _z_. The axis of _a´_, carries in front a pinion _m´_, which sets in motion the wheel _n´_. The latter imparts motion, by means of a pinion and intermediate wheel _o´_, to the wheel _h_ on the doffer cylinder, and consequently to that cylinder on the one hand; and it turns, by the carrier wheel _p´_, a wheel _x_, whose axis is marked also with _x_ in _fig._ 323., upon the other hand. The axis of _x´_, _fig._ 323., carries, towards the middle of the engine, a very broad wheel, which is represented by a small dotted circle. The toothed wheel _v_ of the smooth roller _v´_, _fig._ 323., and the two toothed wheels _o o_, _fig._ 324., of the under rollers _o o_, _fig._ 323., work into that broad wheel. The wheel of the second or delivery fluted roller is seen to be smaller than that of the first, by which means the difference of their velocities is obtained. The large runner _i_ is driven from the main drum pulley, by means of the band _s´_, and the pulley _u´_, _fig._ 323. The said band is crossed twice, and is kept in tension by the pulley _t´_, round which it passes. The motion of the fluted rollers _e_, which feed in the cotton fleece, is effected by means of a bevel wheel _b´_ on the end of the doffer, which works into a similar wheel _c´_ on the oblique axis _d´_ (dotted lines across the drum), of the pinion _e´_ upon the lower end of the same axis which turns the wheel _f´_, upon the under feed roller.

Each of the feed rollers, _fig._ 324., bears a pinion _e e_ at one end, so that the upper roller turns round with the under one. The roller _b_, _fig._ 323., is set in motion by means of its wheel _x´_; which is driven by a wheel _v´_ on the other end of the under feed roller, through the intervention of the large carrier wheel _w´_. The original or first motion of _b_ must be as quick as that of the fluted feed rollers _e_, in order that the former may uncoil as much lap as the latter can pass on.

The annexed table exhibits the proper velocities of the different cylinders and rollers of the carding engine, which, however, are not invariable, but may be modified according to circumstances, by changing the pinions _e´_, _fig._ 323., and _w´_, according to the quality or length of the cotton staple. The velocities stated in the table will be obtained when the pulley _a´_, _fig._ 323., is made greater than _y_ in the proportion of 3 to 2, and the wheels and pinions have the following number of teeth: _m´_, 18; _n´_, 50; its pinion, 18; _h_, 128; _x_, 24; the broad wheel upon the shaft of _x_, 37 teeth; the wheel _o_ of the first fluted roller, 35; that of the second, 21; _v_, 44; _b´_ and _e´_, 54; _e´_, 10; _f´_, 63.

+--------------------------+--------+----------+-----------+---------+
| Names of the parts. |Diameter| Circum- |Revolutions|Velocity.|
| | in | ference | in one | |
| |inches. |in inches.| minute. | |
+--------------------------+--------+----------+-----------+---------+
|Drum _f_ | 35 | 109·9 | 130 | 142·87 |
|Doffer _h_ | 14 | 43·96 | 4·38 | 192·5 |
|Runner or urchin _i´_ | 6·25 | 19·62 | 5· | 98·1 |
|Ditto _h´_ | 3·5 | 11· | 470· | 5170· |
|Fluted feed roller _e_ | 1·167 | 3·664 | 0·696 | 2·55 |
|First drawing roller _o_ | 1· | 3·14 | 68·71 | 215·75 |
|Second ditto | 1·167 | 3·664 | 114·52 | 419·6 |
|Smooth delivery roller _v_| 2·5 | 7·85 | 54·66 | 429·08 |
+--------------------------+--------+----------+-----------+---------+

The operation of the runners, _h´_ and _i´_, becomes very plain on comparing their speed with one another and with that of the main-drum, and taking into account the direction of the card teeth. The cotton wool, taken off from the feed-rollers by the drum, is caught by the opposite teeth of the large runner _i´_, which, on account of its slower surface rotation (98 inches per minute) may be considered to be at rest with reference to the drum, and therefore, by holding the cotton in its teeth, will commence its carding. The small runner _h´_, in consequence of its greater surface velocity (5170 inches per minute) will comb the cotton-wool back out of the teeth of the large runner, but it will give it up in its turn to the swifter teeth of the drum, which, in carrying it forwards, encounters the teeth of the top cards, and delivers up the filaments to their keeping for some time. We thus see how essential the runners are to the perfection as well as to the acceleration of the carding process for ordinary cotton wool, though for the slenderer and longer filaments of the sea-island kind they are not so well adapted. In cleaning the carding-engines the little runner must be looked to every time that the drum is examined. The large runner and the doffer require to be cleaned together. The quantity of cotton spread upon the feed-cloth, the velocity of it, and of the drawing-rollers, must all be carefully adjusted to the grist of the yarn intended to be spun.

Suppose the sizes and velocities to be as represented in the preceding table, that the engine is a double card 36 inches broad, and that it is furnished with a lap from the lap-machine of which 30 feet in length weigh 5 lbs. In one minute the surface of the feed-rollers, _e_, passes 2·55 inches of that lap onwards; in the same time the main drum _f_ will work it off. To card the whole 30 feet, therefore, 141 minutes, or 2 hours and 21 minutes will be required. In this time the circumference of the rollers, _u v_, moves through a space of 141 × 42,908 in. = 5042 ft., and delivers a card-end of that length, weighing 5 lbs., _minus_ 6 per cent. for waste, that is 4 lbs. 11-1/2 oz. One pound will form a riband 1072 feet long, being, according to the English mode of counting, about number 1/3, or 0·357. The extension of the cotton-fleece to this degree proceeds as follows:--In the 141 minutes which the feed-rollers take to introduce the 30 feet of lap, the doffer, _h_, makes 617·58 revolutions, and the comb, or doffer knife, _i_, detaches from the doffer teeth, a thin fleecy web of 2262 feet in length. The first drawing pair of fluted rollers, by its quick motion, with the aid of the funnel, _m_, converts this fleece into a riband 2535 feet long. The second pair of the fluted rollers extends this riband to 4390 feet, since their surface velocity is greater than the first pair in that proportion. The slight elongation (of only 112 feet, or about 1/44) which takes place between the delivery fluted rollers and the smooth cylinders, _v_, _u_, serves merely to keep the card-end steadily upon the stretch without folding. _Fig._ 325. is a plan of the card and the fleece, where _h_ is the cylinder, _n_ is the funnel, _u_ the pressing rollers, and _h´_ the card-ends in the can.

_Figs._ 326, 327. represent skeletons of the old cards to facilitate the comprehension of these complex machines. _Fig._ 326. is a plan; F is the main drum; M M is the doffer knife or comb; G, the carded fleece hemmed in by the funnel _a_, pressed between the rollers _b_, and then falling in narrow fillets into its can. _Fig._ 327. K L are the feed rollers; A B, the card drum; C D, the tops; E F, the doffer card; M N, the doffer knife; _d_, _b_, _c_, the card-end passing between compressing rollers into the can _a_.

_The drawing and doubling_ are the next operation. The ends, as they come from the cards, are exceedingly tender and loose, but the filaments of the cotton are not as yet laid so parallel with each other as they need to be for machine spinning. Before any degree of torsion therefore be communicated, a previous process is required to give the filaments a level arrangement in the ribands. The drawing out and doubling accomplish this purpose, and in a manner equally simple and certain. The means employed are drawing-rollers, whose construction must here be fully explained, as it is employed in all the following machines; one example of their use occurred, indeed, in treating of the cards.

Let _a_ and _b_, _fig._ 328., represent the section of two rollers lying over each other, which touch with a regulated pressure, and turn in contact upon their axes, in the direction shown by the arrows. These rollers will lay hold of the fleecy riband presented to them at _a_, draw it through between them, and deliver it quite unchanged. The length of the piece passed through in a given time will be equal to the space which a point upon the circumference of the roller would have percured in the same time; that is, equal to the periphery of one of the rollers multiplied by the number of its entire revolutions. The same thing holds with regard to the transmission of the riband through between a second pair of rollers, _c_, _d_, and a third, _e_, _f_. Thus the said riband issues from the third pair exactly the same as it entered at _a_, provided the surface speed of all the rollers be the same. But if the surface speed of _c_ and _d_ be greater than that of _a_ and _b_, then the first-named pair will deliver a greater length of riband than the last receives and transmits to it. The consequence can be nothing else in these circumstances than a regulated drawing or elongation of the riband in the interval betwixt _a_, _b_, and _c_, _d_, and a condensation of the filaments as they glide over each other, to assume a straight parallel direction. In like manner the drawing may be repeated by giving the rollers, _e_, _f_, a greater surface speed than that of the rollers, _c_ and _d_. This increase of velocity may be produced, either by enlarging the diameter, or by increasing the number of turns in the same time, or finally by both methods conjoined. In general the drawing-machine is so adjusted, that the chief elongation takes place between the second and third pairs of rollers, while that between the first and second is but slight and preparatory. It is obvious, besides, that the speed of the middle pair of rollers can have no influence upon the amount of the extension, provided the speed of the first and third pair remains unchanged. The rollers, _a_, _b_, and _c_, _d_, maintain towards each other continually the same position, but they may be removed with their frame-work, more or less, from the third pair, _e_, _f_, according as the length of the cotton staple may require. The distance of the middle point from _b_ and _d_, or its line of contact with the upper roller, is, once for all, so calculated, that it shall exceed the length of the cotton filaments, and thereby that these filaments are never in danger of being torn asunder by the second pair pulling them while the first holds them fast. Between _d_ and _f_, where the greatest extension takes place, the distance must be as small as it can be without risk of tearing them in that way; for thus will the uniformity of the drawing be promoted. If the distance between _d_ and _f_ be very great, a riband passing through will become thinner, or perhaps break in the middle; whence we see that the drawing is more equable, the shorter is the portion submitted to extension at a time, and the nearer the rollers are to each other, supposing them always distant enough not to tear the staple.

The under rollers _b d f_ are made of iron, and, to enable them to lay firmer hold of the filaments, their surfaces are fluted with triangular channels parallel to their axes. The upper rollers, _a c e_, are also made of iron, but they are smooth, and covered with a double coating, which gives them a certain degree of softness and elasticity. A coat of flannel is first applied by sewing or gluing the ends, and then a coat of leather in the same way. The junction edges of the leather are cut slanting, so that when joined by the glue (made of isinglass dissolved in ale) the surface of the roller may be smoothly cylindrical. The top rollers are sometimes called the _pressers_, because they press by means of weights upon the under ones. These weights are suspended to the slight rods _k k´_; of which the former operates on the roller _e_ alone, the latter on the two rollers _a_ and _e_ together. For this purpose the former is hung to a C shaped curve _i_, whose upper hook embraces the roller _e_; the latter to a brass saddle _h_, which rests upon _a_ and _c_. A bar of hard wood, _g_, whose under surface is covered with flannel, rests, with merely its own weight, upon the top rollers, and strips off all the loose hanging filaments. Similar bars with the same view are made to bear up under the fluted rollers _b d f_, and press against them by a weight acting through a cord passing over a pulley. Instead of the upper dust-covers, light wooden rollers covered with flannel are occasionally applied.

Were the drawing of a riband continued till all its fibres acquired the desired degree of parallelism, it would be apt, from excessive attenuation, to tear across, and thereby to defeat the purpose of the spinner. This dilemma is got rid of in a very simple way, namely, by laying several ribands together at every repetition of the process, and incorporating them by the pressure of the rollers. This practice is called _doubling_. It is an exact imitation of what takes place when we draw a tuft of cotton wool between our fingers and thumb in order to ascertain the length of the staple, and replace the drawn filaments over each other, and thus draw them forth again and again, till they are all parallel and of nearly equal length. The doubling has another advantage, that of causing the inequalities of thickness in the ribands to disappear, by applying their thicker to their thinner portions, and thereby producing uniformity of substance.

The drawing frame, as shown in section in _figs._ 328. 330., and in a back view in _fig._ 329., will require, after the above details, little further explanation. _l l_ are the weights which press down the top rollers upon the under ones, by means of the rods _k k´_ and hook _i_. Each fluted roller is, as shown at _f_, _fig._ 329., provided in the middle of its length with a thinner smooth part called the _neck_, whereby it is really divided into two fluted portions, represented by _e e_ in the figure. Upon this middle neck in the pressure rollers, the hook _i_ and the saddle _h_ immediately bear, as shown in the former _fig._ 328. The card-ends, to the number probably of six, are introduced to the drawing frame either from tin cans, placed at _e e_, _fig._ 330., and at A, _fig._ 329., or from lap-bobbins; and, after passing through it, the ribands or slivers are received either into similar tin cans, as _g_, or upon other lap-bobbins upon the other side. These appendages may be readily conceived, and are therefore not exhibited in all the drawings. Three of the slivers being laid together, are again introduced to the one fluted portion _a b_, _fig._ 328., and three other slivers to the other portion. The sloping curved tin or brass plate _s_, _fig._ 329., with its guide pins _t_, serves to conduct the slivers to the rollers. When the two threefold slivers have passed through between the three pairs of rollers, and been thereby properly drawn, they run towards each other in an oblique direction, behind the last roller pair _e f_, _fig._ 328., and unite, on issuing through the conical funnel _m_, _fig._ 329., into a single riband or spongy sliver; which is immediately carried off with equable velocity by two smooth cast-iron rollers, _n o_, _fig._ 329. and 330. and either dropped into a can, or wound upon a large bobbin. The surface speed of these rollers is made a trifle greater than that of the delivery drawing rollers, in order to keep the portion of sliver between them always in an extended state. Four fluted drawing portions are usually mounted in one drawing frame, which are set a-going or at rest together. To save all unnecessary carrying of the cans from the back to the front of the frame, the drawing heads are so placed, that the first and third, discharge their slivers at the one side, and the second and fourth at the other. By this arrangement, the cans filled behind one head, are directly pushed aside in front of the next drawing head; by which alternate distribution the work goes on without interruption.

The _fast_ pulley _u_, _fig._ 330., by which the whole machine is driven, derives its motion from the main shaft of the mill by means of the band _w_. The similar pulley _x_, which sits loose upon the axis, and turns independently of it, is called the loose pulley; both together being technically styled _riggers_. When the operative desires to stop the machine, he transfers the band from the fast to the loose pulley by means of a lever, bearing a fork at its end, which embraces the band. Upon _y_, four pulleys such as _x_ are fixed, each of which sets in motion a drawing head, by means of a band like _w_ going round the pulleys _x_ and _u_. On account of the inverted position of the heads, which requires the motion of _u_ to be inverted, the bands of the first and third heads are open, but those of the second and fourth are crossed. Every head is provided with a loose pulley _v_, as well as the fast pulley _u_, in order to make the one stop or move without affecting the others. The shaft of the pulley _u_ is the prolonged shaft of the backmost fluted roller _f_. It carries besides a small pulley _q_, which, by means of the band _r_, and the pulley _p_, _fig._ 329., sets in motion the undermost condensing roller _o_. The upper roller _n_, presses with its whole weight upon it, and therefore turns by friction. The toothed wheel-work, by which the motions are communicated from the backmost fluted roller to the middle and front ones, are seen in _fig._ 330.

The wheel _f_, _fig._ 328., of 20 teeth, works in a 44-toothed carrier-wheel, on whose axis there are two smaller wheels; 2 with 26 teeth, and 1 with 22 teeth. The wheel _d_, _fig._ 330., of the middle roller, and the wheel _b_ of the front roller, are set in motion by other carrier wheels; the first has 27 teeth, and the last 40. For every revolution of _b_, the roller _d_ makes nearly 1-3/4 turns, and the roller _f_, 4 revolutions. The top rollers revolve, as we have stated, simply by the friction of contact with the lower ones. Now suppose the diameter of the rollers _b_ and _d_ to be 1 inch or 12 lines, that of _f_, 1-1/4 inches or 15 lines, the surface velocities of the three pairs of rollers in the series will be as 1, 1-3/4, and 5. Every inch of the cotton sliver will be therefore extended between the first and second pair of rollers into 1-3/4 inches, and between the second and third or delivery pair into 5 inches; and after the sliver has passed through all the four drawing heads, its length will be increased 625 times = 5 × 5 × 5 × 5.

The further the drawing process is pushed, the more perfectly will its object be accomplished; namely the parallelism of the filaments. The fineness of the appearance of the sliver after the last draught depends upon the number of doublings conjointly with the original fineness and number of drawings. The degree of extension may be increased or diminished, by changing the wheels in _fig._ 330., for others with a different number of teeth. Thus the grist or fineness of the sliver may be modified in any desired degree; for, when the subsequent processes of the mill remain the same, the finer the drawings the finer will be the yarn. For spinning coarse numbers or low counts, for example, six card-ends are usually transmitted through the first drawing head, and converted into one riband. Six such ribands again form one in the second draught; six of these again go together into the third sliver; and this sliver passes five-fold through the last draught. By this combination 1080 of the original card-ends are united in the finished drawn sliver = 6 × 6 × 6 × 5. The fineness of the sliver is, however, in consequence of these doublings not increased but rather diminished. For, by the drawing, the card-end has been made 625 times longer, and so much smaller; by the doubling alone it would have become 1080 times thicker; therefore the original grist is to the present as 1, to the fraction 625/1080; that is, supposing 1072 feet of the riband delivered by the card to weigh one pound, 625 feet, the sliver of the last drawing, will also weigh a pound, which corresponds in fineness to number 0·24, or nearly 1/4.

The rearmost or last drawing roller has a circumference of nearly 4 inches, and makes about 150 revolutions per minute; hence, each of these drawing heads may turn off 35,000 feet of sliver in 12 hours.

Some manufacturers have lately introduced a double roller beam, and a double draught at the same doubling, into their drawing frames. I have seen this contrivance working satisfactorily in mills where low counts were spun, and where the tube roving frame was employed; but I was informed by competent judges, that it was not advisable where a level yarn was required for good printing calicoes.

The loss which the cotton suffers in the drawing frame is quite inconsiderable. It consists of those filaments which remain upon the drawing rollers, and collect, in a great measure, upon the flannel facing of the top and bottom cleaner bars. It is thrown among the top cleanings of the carding engine. When from some defect in the rollers, or negligence in piecing the running slivers, remarkably irregular portions occur in the ribands, these must be torn off, and returned to the lap machine to be carded anew.

The fifth operation may be called the _first spinning process_, as in it, the cotton sliver receives a twist; whether the twist be permanent as in the bobbin and fly frame, or be undone immediately, as in the tube-roving machine. In fact, the elongated slivers of parallel filaments could bear little further extension without breaking asunder, unless the precaution were taken to condense the filaments by a slight convolution, and at the same time to entwine them together. The twisting should positively go no further than to fulfil the purpose of giving cohesion, otherwise it would place an obstacle in the way of the future attenuation into level thread. The combination of drawing and twisting is what mainly characterizes the spinning processes, and with this fifth operation therefore commences the formation of yarn. As however a sudden extension to the wished-for fineness is not practicable, the draught is thrice repeated in machine spinning, and after each draught a new portion of torsion is given to the yarn, till at last it possesses the degree of fineness and twist proportioned to its use.

The preliminary spinning process is called _roving_. At first the torsion is slight in proportion to the extension, since the solidity of the still coarse sliver needs that cohesive aid only in a small degree, and looseness of texture must be maintained to facilitate to the utmost the further elongation.

_Fig._ 331. is a section of the can roving frame, the ingenious invention of Arkwright, which till within these 14 years was the principal machine for communicating the incipient torsion to the spongy cord furnished by the drawing heads. It differs from that frame in nothing but the twisting mechanism; and consists of two pairs of drawing rollers, _a_ and _b_, between which the sliver is extended in the usual way; _c_ are brushes for cleaning the rollers; and _d_ is the weight which presses the upper set upon the lower. The wiping covers (not shown here) rest upon _a b_. The surface speed of the posterior or second pair of rollers is 3, 4, or 5 times greater than that of the front or receiving pair, according to the desired degree of attenuation. Two drawn slivers were generally united into one by this machine, as is shown in the figure, where they are seen coming from the two cans _e e_, to be brought together by the pressure rollers, before they reach the drawing rollers _a b_. The sliver, as it escapes from these rollers, is conducted into the revolving conical lantern _g_, through the funnel _f_ at its top. This lantern-can receives its motion by means of a cord passing over a pulley _k_, placed a little way above the step on which it turns. The motion is steadied by the collet of the funnel _f_, being embraced by a brass busk. Such a machine generally contained four drawing heads, each mounted with two lanterns; in whose side there was a door for taking out the conical coil of roving.

The motion imparted to the back roller by the band pulley or rigger _m_, was conveyed to the front one by toothed wheel work.

The vertical guide pulley at bottom _n_, served to lead the driving band descending from the top of the frame round the horizontal whorl or pulley upon the under end of the lantern. The operation of this can-frame was pleasing to behold; as the centrifugal force served both to distribute the soft cord in a regular coil, and also to condense a great deal of it most gently within a moderate space. Whenever the lantern was filled, the tenter carried the roving to a simple machine, where it was wound upon bobbins by hand. Notwithstanding every care in this transfer, the delicate texture was very apt to be seriously injured, so as to cause corresponding injuries in every subsequent operation, and in the finished yarn. Messrs. Cocker and Higgins, of Salford, had the singular merit, as I have said, of superseding that beautiful but defective mechanism, which had held a prominent place in all cotton mills from almost the infancy of the factory system, by the following apparatus.

_The Bobbin and Fly frame_ is now the great roving machine of the cotton manufacture; to which may be added, for coarse spinning, the tube roving frame. Of such a complicated machine as the bobbin and fly frame, it is not possible to give an adequately detailed description in the space due to the subject in this Dictionary. Its mechanical combinations are however so admirable as to require such an account as will make its functions intelligible by the general reader.

_Fig._ 332. exhibits a back view of this machine; and _fig._ 333. a section of some of the parts not very visible in the former figure. The back of the machine is the side at which the cotton is introduced between the drawing rollers.

The cans, or lap-bobbins filled with slivers at the drawing frame, are placed in the situation marked B, _fig._ 333., in rows parallel with the length of the machine. The sliver of each can or the united slivers of two contiguous cans are conducted upwards along the surface of a sloping board _f_, and through an iron staple or guide _e_, betwixt the usual triple pair of drawing rollers, the first of which is indicated by _a_, _b_. In _fig._ 332., for the purpose of simplifying the figure, the greater part of these rollers and their subordinate parts are omitted. After the slivers have been sufficiently extended and attenuated between the rollers, they proceed forwards, towards the spindles _i i i_, where they receive the twist, and are wound upon the bobbins _h_. The machine delineated contains thirty spindles, but many bobbin and fly frames contain double or even four times that number. Only a few of the spindles are shown in _fig._ 332., for fear of confusing the drawing.

With regard to the drawing functions of this machine, I have already given abundant explanation, so far as the properties and operation of the rollers are concerned. The frame-work of this part of the machine, called the _roller-beam_, is a cast iron bench, upon which nine bearers _c_, are mounted for carrying the rollers. The fluted rollers _a a a_, _fig._ 334., are constructed in four pieces for the whole length, which are parted from each other by thinner smooth cylindric portions _z_, called necks. Seven such partings for four rollers, and one parting for two rollers, constitute together the 30 fluted rollers of which the whole series consists. The coupling of these roller subdivisions into one cylinder, is secured by the square holes _x_, and square pins _y_, _fig._ 334., which fit into the holes of the adjoining subdivision. The top or pressure rollers _b_, are two-fold over the whole set; and the weighted saddle presses upon the neck _w_, which connects every pair, as was already explained under _fig._ 329. These weights _g_, _g_, _fig._ 333., are applied in this as in the _drawing frame_; _d_, are the bars faced with flannel for cleaning the top rollers. A similar bar is applied beneath the rollers, to keep the flutings clean.

The structure and operation of the spindles _i_, may be best understood by examining the section _fig._ 335. They are made of iron, are cylindrical from the top down to _a_², but from this part down to the steel tipt rounded points they are conical. Upon this conical portion there is a pulley _k_, furnished with two grooves in its circumference, in which the cord runs that causes the spindle to revolve. The wooden bobbin _h_, is slid upon the cylindrical part, which must move freely upon it, as will be presently explained. To the bobbin another two-grooved pulley or whorl _q_ is made fast by means of a pin _r_, which passes through it; by removing this pin, the bobbin can be instantly taken off the spindle. The upper end of the spindle bears a fork _s t_, which may be taken off at pleasure by means of its left-handed screw; this fork or flyer, has a funnel-formed hole at _v_. One arm of the fork is a tube _s_, _u_, open at top and bottom; the leg _t_, is added merely as a counterpoise to the other. In _fig._ 333., for the sake of clearness, the forks or flyers of the two spindles here represented are left out; and in _fig._ 332. only one is portrayed for the same reason. It is likewise manifest from a comparison of these two figures that the spindles are alternately placed in two rows, so that each spindle of the back range stands opposite the interval between two in the front range. The object of this distribution is economy of space, as the machine would need to be greatly longer if the spindles stood all in one line. If we suppose the spindles and the bobbins (both of which have independent motions) to revolve simultaneously and in the same direction, their operation will be as follows: The sliver properly drawn by the fluted rollers, enters the opening of the funnel _v_, proceeds thence downwards through the hole in the arm of the fork, runs along its tube _u_, _s_, and then winds round the bobbin. This path is marked in _fig._ 335. by a dotted line.

The revolution of the spindles in the above circumstances effects the twisting of the sliver into a soft cord; and the flyer _s_, _t_, or particularly its tubular arm _s_, lays this cord upon the bobbin. Were the speed of the bobbins equal to that of the spindles, that is, did the bobbin and spindle make the same number of turns in the same time, the process would be limited to mere twisting. But the bobbin anticipates the flyers a little, that is, it makes in a given time a somewhat greater number of revolutions than the spindle, and thereby effects the continuous winding of the cord upon itself. Suppose the bobbin to make 40 revolutions, while the spindle completes only 30; 30 of these revolutions of the bobbin will be inoperative towards the winding-on, because the flyers follow at that rate, so that the cord or twisted sliver will only be coiled 10 times round the bobbin, and the result as to the winding-on will be the same as if the spindle had stood still, and the bobbin had made 40 - 30 = 10 turns. The 30 turns of the spindles serve, therefore, merely the purpose of communicating twist.

The mounting and operation of the spindles are obviously the same as they are upon the household flax wheel. In the bobbin and fly frame there are some circumstances which render the construction and the winding-on somewhat difficult, and the mechanism not a little complicated. It may be remarked in the first place, that as the cord is wound on, the diameter of the bobbin increases very rapidly, and therefore every turn made round it causes a greater length of roving to be taken up in succession. Were the motions of the bobbins to continue unchanged in this predicament, the increased velocity of the winding-on would require an increased degree of extension, or it would occasion the rupture of the cord, because the front fluted rollers move with uniform speed, and therefore deliver always the same length of sliver in the same time. It is therefore necessary to diminish the velocity of the bobbins, or the number of their turns, in the same proportion as their diameter increases, in order that the primary velocity may remain unchanged. Moreover, it is requisite for the proper distribution of the cord upon the bobbin, and the regular increase of its diameter, that two of its successive convolutions should not be applied over each other, but that they should be laid close side by side. This object is attained by the up and down sliding motion of the bobbin upon the spindle, to the same extent as the length of the bobbin barrel. This up and down motion must become progressively slower, since it increases the diameter of the bobbin at each range, by a quantity equal to the diameter of the sliver. What has now been stated generally, will become more intelligible by an example.

Let it be assumed that the drawing rollers deliver, in 10 seconds, 45 inches of roving, and that this length receives 30 twists. The spindles must, in consequence, make 30 revolutions in 10 seconds, and the bobbins must turn with such speed, that they wind up the 45 inches in 10 seconds. The diameter of the bobbin barrels being 1-1/2 inches, their circumference of course 4-1/2 inches, they must make 10 revolutions more in the same time than the spindles. The effective speed of the bobbins will be thus 30 + 10 = 40 turns in 10 seconds. Should the bobbins increase to 3 inches diameter, by the winding-on of the sliver, they will take up 9 inches at each turn, and consequently 45 inches in 5 turns. Their speed should therefore be reduced to 30 + 5 = 35 turns in 10 seconds. In general, the excess in number of revolutions, which the bobbins must make over the spindles, is inversely as the diameter of the bobbins. The speed of the bobbins must remain uniform during the period of one ascent or descent upon the spindle, and must diminish at the instant of changing the direction of their up and down motion; because a fresh range of convolutions then begins with a greater diameter. When, for example, 30 coils of the sliver or roove are laid in one length of the bobbin barrel, the bobbin must complete its vertical movement up or down, within 30 seconds in the first case above mentioned, and within 60 seconds in the second case.

The motions of the drawing rollers, the spindles, and bobbins, are produced in the following manner:--A shaft _c´_, _fig._ 332. and 333., extending the whole length of the machine, and mounted with a fly wheel _d´_, is set in motion by a band from the running pulley upon the shaft of the mill, which actuates the pulley _a´_. _b´_ is the loose pulley upon which the band is shifted when the machine is set at rest. Within the pulley _a´_, but on the outside of the frame, the shaft _c´_ carries a toothed wheel _b_² with 50 teeth, which by means of the intermediate wheel _c_² turns the wheel _d_² upon the prolonged shaft of the backmost fluted roller (_m_², _fig._ 333.) This wheel _d_² has usually 54 teeth; but it may be changed when the roove is to receive more or less twist; for as the spindles revolve with uniform velocity, they communicate the more torsion the less length of sliver is delivered by the rollers in a given time. Upon the same shaft with _d_², a pinion _e_² of 32 teeth is fixed, which works in a wheel _f_² of 72 teeth. Within the frame a change pinion _g_² is made fast to the shaft of _f_². This pinion, which has usually from 24 to 28 teeth, regulates the drawing, and thereby the fineness or number of the roving. It works in a 48-toothed wheel _h_² upon the end of the backmost fluted roller _a_, _fig._ 333. The other extremity of the same roller, or, properly speaking, line of rollers, carries a pinion _l_², furnished with 26 teeth, which, by means of the broad intermediate wheel _k_², sets in motion the pinion _i´_² of 22 teeth upon the middle roller. When the diameter of all the drawing rollers is the same, suppose 1 inch, their proportional velocities will be, with the above number of teeth in the wheel work, if _g_² have 24 teeth, as 1 : 1·18 : 4·5; and the drawn sliver will have 4-1/2 times its original length. The front or delivery roller of the drawing frame is of late years usually made 1-1/4 or 1-3/8 inches in diameter. If 625 feet of the sliver from the drawing frame weighed one pound, 2790 feet of the roving will now go to this weight, and the number will be 1·12; that is, 1 hank and 12 hundredths to the pound. The front pair of fluted rollers makes about 90 revolutions, and delivers 282·6 inches of roving in the minute, when of one inch diameter.

The spindles _i_, (_fig._ 332. and 333.), rest, with their lower ends, in steps _l_, which are fixed in an immoveable beam or bar _m_. To protect it from dust and cotton filaments, this beam is furnished with a wooden cover _n_, in which there are small holes for the passage of the spindles right over the steps. In _fig._ 332., two of the eight covers _n_, which compose the whole range _m_, are removed to let the steps be seen. The cylindrical part of each spindle passes through a brass ring _o_; and all these 30 rings, whose centres must be vertically over the steps _l_, are made fast to the copping beam _p_. This beam is so called, because it is destined not merely to keep the spindles upright by the rings attached to it, but, at the same time, to raise and lower along the spindles the bobbins which rest on these rings; for which purpose the two racks, or toothed bars _m_² _m_², made fast to it, are designed, as will be presently explained. To effect the revolution of the spindles, there are attached to the main shaft _c´_ two whorls or pulleys _e´ f´_, each bearing four grooves of equal diameter. Each of these pulleys puts one half of the spindles in motion, by means of a cord, which, after going round the whorls _k_, turns four times about the pulleys of the shaft _c´_. Two guide pulleys _h´_, each four-grooved, and two others _i´_, with a single groove, which turn independently of the others, upon the above shaft, serve to give the whorl cords the proper direction, as well as to keep them tight. The spindles revolve 200 times or thereby in the minute; and therefore impart two turns or twists to every three inches of the roving.

The revolution of the bobbins is independent of that of the spindles, although it likewise proceeds from the shaft _c´_, and differs from it in being a continually retarded motion. The simplest method of effecting this motion, is by means of the wooden or tin plate cone _k´´_, which revolves equally with the shaft _c´_, and at the same time slides along it.