As will be seen from Fig. 529, which represents the feeding as taking place in the room above the machine, an endless lattice A, on which the cotton is evenly laid, delivers it to two pairs of rollers B, the second revolving more quickly than the first ; these convey it to the tube, where it is instantly seized by the air current. During its aerial passage, sand, dirt, dust, small stones, and all heavy or dangerous substances accidentally present with the cotton, are dropped upon the bottom of the tube. In order to secure the abstraction of these, Messrs. Lord invented and patented their grated trunks. Intermediately between the feed table and the opener, several lengths of these tubes C are inserted. Seen in section, they are shaped. Inside these, at short distances apart, plates of sheet iron are placed athwart, and slightly inclined against the direction of the current, and reaching about half-way to the crown of the tube. The spaces between these plates form cells for the reception of extraneous matter, which, dropping out of the cotton, is retained in them ; it is removed daily through the bottom of the tube, which opens downwards, and is hinged for the purpose. These cells prove very efficient, as is shown by the quantity of dust that is taken ont of those in the front, and its gradual diminution towards the last ; and by the small amount of foreign matter thrown off in the opener and scutcher.
The opener consists of a horizontal shaft a, carrying a series of accurately balanced arms d, arranged radially on the shaft at several inches apart. These £1.1=8 are of cast iron, with steel blades bolted firmly to their extremities. The length of these arms is, at the small end nearest the tube, about 18 in. ; it increases gradually as the opposite side is approached, terminating with 28 in. When revolving, the arms describe the figure of a cone. A conical grid surrounds the beaters, constructed by the junction of two rings of unequal diameter by means of straight steel bars. This grid can be moved endwise upon the shaft, by means of the wheel beneath the tube, at the left extremity of the machine. The bars are fixed at the delivei y end, but are capable of adjustment at the feed end, in order to increase or diminish the distance from the beater, according to the length of staple or quality of cotton that has to be treated. On the mune shaft, at the delivery end of the beater, is a powerful disc fan, which, in conjunction with the other fan p, whose specific function is to exhaust the dust-cages f f , and which is situated below them, draws the cotton from the extremity of the feed-pipe, through the beater, to the dust-cages ; at this point, the ootton is received by two small rollers, that deliver it to the beater g of the scutcher, where it undergoes further opening and cleansing, by a process resembling the one it has just passed through, except as regards the form of the heater. The scutcher and lap attachment, which receives the cotton at this point, will be described in connection with the next machine.
Scutching.—Scutching has a twofold object : to further cleanse the cotton, and to form a lap. If the raw material has not, in the previous stage, passed through an opener with a lap-forming attachment, it arrives at this point in bulk, and but partially cleansed and opened. Scutching is
the first stage in the series of arrangements that produce the finished article. The lap is a continuous sheet of cotton, about 40 in. wide, which is formed into a roll of convenient length to suit the maohinery. In it the fibres lie in all directions across each other, no attempt having yet beert made to arrange them in parallel order.
The soutcher has undergone many changes ere attaining its present comparative perfection. Amongst makers, the result is unanimity regarding the main features of the machine, tempered by differences on points of detail. The latter need not be brought fully before the reader: it will serve to describe one or two of the most popular and representative forms.
The Crighton scutcher is a well-known machine. It possesses a lattice-creeper, on which the cotton is evenly laid, in measured spaces, after being weighed. A pair of small fluted rollers take the cotton from the lattice, and pass it to a beater, having two blades encased in a cylinder ; a quarter-section of the latter, from the fluted rollers to the bottom, is composed of a grid. The beater, having a speed of about 1000 revolutions a minute, strikes the cotton with great force from the rollers against this grid, causing leaves, motes, and other impui ities, to fall through. Parallel with the bottom of the cylinder, is a passage, leading to the pair of dust-cages situated at the back. Along this, the cotton is drawn by the current induced by the exhaust-fans. The bottom of this passage is formed by a lattice, arranged with its surface open, for the reception of impurities that may have passed the first grids. This lattiee moves over three rollers arranged thus--• . •, and, travelling in a direction opposite to that followed by the cotton, it carries away only substances of greater specific gravity than the fibres under treatment, and discharges them into the dust-cavity beneath the grid. The loose cotton is evenly distributed by the current over the wires of the dust-cages, as they slowly revolve. These wires, whilst holding the cotton, permit the extraction, through their interstices, of the fine particles of dust that may have come on the current of air along with the fibre,—hence their name. The perfect removal of sand or grit is of great importance, because were it to pass along with the cotton through subsequent processes, it would seriously damage the machinery. The cages join the cotton deposited upon them into one sheet, which is removed by a pair of small fluted rollers ; these pass it to the compression-rollers, whence it escapes to the lap roller ; this, by means of a pair of large fluted rollers, revolving in the same direction, takes on the sheet of cotton until it has formed a thick roll, technically called a "lap." From the first handling of cotton in the mill, the object is to obtain a clean, round, even thread of yarn. In order to secure this, it is necessary that the scutcher or first lap machine should. be carefully fed, the cotton being apread evenly upon the lattice, so that it may pass through at a uniform rate. But it is not always possible to ensure this with hand labour, and mechanical appliances have in consequence been invented for the purpose.