A careful assortment of the qualities of the flax is exceedingly important, as upon the skill with which this has been done, and the care with which it is subsequently preserved from becoming intermixed, depend satisfactory results in the spinning process. The points to be observed in sorting are fineness, length, strength, colour, and cleanli ness; and these are required to be noted during the half-minute or so that a piece is in the hands of the operator undergoing dress ing. It is exceedingly difficult to secure a perfect assortment of flax into its different qualities, because whatever principle is adopted as tho basis, it is sure to fail in one point or other to give a good classification. If more than one system be em ployed, the number of sorts becomes unmanageable, and leads to confusion, whilst both warp and weft yarns are apt to be injured by the presence of fibre that ought to have been in the opposite class.
The most satisfactory ar rangement of the various pro cesses is to have the roughing, machining, and sorting in separate apartments, each under the care of an ovorlooker respon sible for the proper performance of the work committed to his charge. The roughing - room should be in immediate proximity to the rough-flax store on one hand and to the machine-room on the other. The sorting-room should be provided with plenty of light, a northern aspect being the best, and efficient ventilation. It should also be near the machine-room on one side, and the dressed flax and tow stores on the other. This arrangement entails less expense in handling, and less liability of spoiling the work or making waste through carelessness. This plan can, however, only be adopted in large establishments. In small ones, it is generally most economical to have these processes upon one floor, under the observation of a principal overlooker, but so arranged that the work shall proceed with the least interruption and handling, and in the most direct way.
Preparing.—On the efficiency and skill with which the " preparing " is performed, the best results almost entirely depend. Here the advantages of the preceding operations, however well managed, can be easily neutralized ; whilst defective or negligent work at this stage cannot have its consequences eliminated subsequently. With practical knowledge and conscientious care at this point, from good material the very beet results may be anticipated, whilst from an indifferent quality a product may be obtained that could not justly be expected.
The flax, dressed and sorted as previously described, is brought to the ''spreading-frame," which is the first machine through which it passes in the preparation. Its function is analogous to that of the carding-engine in cotton manufacture, as the material in its passage through it is first con verted into a sliver. It is a machine of about 10 ft. in length from back to front, and about 4-5 ft.
in width and height. A plain iron roller, called the " boss-roller," which may be 2-4 in. in diem., extends across the frame about 31 ft. above the floor, being supported by journals resting in bearings in the frame. In its front is a cast-iron plate with diagonal slits, called the "doubling-plate." These slits are equal in number to the rows of gills in each head of fallers. These gills and fallers are precisely similar in construction, and have the same function, as those described and illustrated in the article on Jute Manufacture, to which the reader is referred (see p. 1180-1). Upon the boss
roller, are pressing-rollers, composed of wood, and iu shape corresponding to the bosses of the preceding roller. Two of these wood bosses are fixed upon one axle, and work in pairs. They are adjusted at the angle which will deliver the sliver to the doubling-plate in the best form. Upon the space between these bosses, are suspended hooks, to which springs adjustable by thumb-screws ere attached, by which the force wherewith the presser-rollers bear upon the boss-roller can be graduated according to requirement. The back- or feed-rollers of the spread-board are set close behind the travelling gills, and at such a height as to allow the pins of the gills, when being lifted from the lower screws, to penetrate the fibre. Behind the feed-rollers, is a revolving leather apron ; and between them, a conductor-plate. Fig. 927 represents the spreading-frame, as made by Fairbairn, Kennedy and Naylor, of Leeds.
The operation is as follows: the attendant girl, called a " spreader," takes the pieces from the sorter's bunch, and divides them into as many portions as are consistent with the nature of the work in process—which may require light, medium, or heavy spreading, and then proceeds to /ay them upon the revolving apron as evenly as possible, with the " top-end " nearest the feed-rollers, taking especial care not to toss the fibres, nor disturb their parallel arrangement. In this manner, the fibre is fed upon the revolving apron in an even and straight line down its length. Care is taken that each piece shall fall a little behind the preceding one, so that the feed thus formed may not enter the gills too heavy, and yield too thick a sliver. The flax, after being spread, is delivered by the revolving sheets into the conductors, thence passing through the feed-rollers to the gills, which travel slightly more rapidly than the feed-rollers revolve.' The fibre is next delivered over brass guide-plates to the boss- and pressing-rollers, which have a much quicker revolution than the feed-rollers. By these, its foremost and longest portions are drawn quickly away in succession in a light, continuous, ribbon-like form, constituting the sliver. In this form, it is conducted to the doubling-plate, and passed through a diagonal slit under the plate, where it is joined by the others, except one from the same head, all passing together up through the last slit, where it unites with the outside sliver which has not been through a slit, and, in this combined form, the whole pass through the delivery-rollers and are deposited in long cylindrical cans, termed "sliver-cans." Upon the end of the delivery-roller, is fixed a small worm, which gears into a wheel, and this into another, called the " bell-wheel," one revolution of which rings a bell, indicating that a given length has been deposited in the can, which is then removed by the attendant, who imme diately puts an empty one in its place. The tenuity of the sliver depends upon the lightness or thin spreading of the material upon the feed-aprons, and upon the draft of the boss-roller. These points are arranged according to requirement, and this baying been accomplished, the weight of the sliver, or the number of yards per lb., can be perfectly controlled, being simply a matter of calculation.