After having gone through the gills and delivery-rollers, the attenuated sliver passes downwards through the neck of the flier, next through a groove in the leg, and then through the eye to the barrel of the bobbin. Generally the arrangement is that the spindle shall "lead," and the bobbin " follow " : that is, that the revolutions of the bobbin shall be so many less than those of the spindle, so as to enable it to wind up the roving as it is delivered from the rollers. When the spindles are filled with a set or " doff " of bobbins, as a full complement is called, the barrels are bare, and consequently at their least circumference, and will take up the rove at the slowest rate. In starting, therefore, they require to lag more behind their " leader " than at any other point. As the circumference of the barrel increases with every layer of rove deposited upon it, the rove would be taken up more quickly every time, and would consequently be first drafted much finer, and then broken, were the speeds of the flier and the bobbin constant at the proportionate rate at which work was commeoced. But this result is obviated by the provision of an appliance by which the proportionate speeds are changed, the bobbin being accelerated as the circumference of its winding-surface enlarges by the addition of successive layers of roving. This is called the differential driving-gear, explained in the article on Jute, before referred to. Sometimes " cones " are employed to obtain the same result. When the latter are adopted, the upper cone is connected with the gearing of the frame, and its speed is constant. The driven cone is of the same shape as the driver, but is fixed in the reverse way : that is, the smallest diameter of one is set opposite the largest diameter of the other. The connection is by means of a strap, and this being traversed along the cones, gives a constantly varying rate of revolution to the driven cone, which is so adjusted as to accelerate the speed of the bobbin, until, when full, it very nearly equals that of the spindle. The belt is shifted on tbe'cones about I in., or other necessary distance, every time the traverse-rail in rising or falling arrives at the end of its course, and a fresh layer of rove has been placed upon the bobbin. After doffing the set of bobbins, and filling the frame anew, the differential driving-gear is readjusted, so as to commence again at correct speed.
The temperature of the•rooms in which preparing is carried on should be preserved as uniform as possible, not to fall below 15i° (60° F.), nor exceed 21° (70° F.). This is not difficult to accomplish in a well-found mill, and tends greatly to the production of satisfactory work. An excess of heat or cold, dryness or moisture, causes the sliver to lap round the rollers, the result being unsatisfactory work, diminished production, and increased waste. When, owing to atmo spheric conditions, the air of the rooms is heavy with moisture, it should be warmed and dried by the introduction of steam into the warming pipes, regulated until normal conditions are restored. In the sharp, dry frosts of winter, or during the prevalence of dry east winds, the same tendency of the fibre to lap is often seen ; in either case, the evil will be obviated by having a few jets in a steam-pipe and allowing the steam to blow into the room, when the moist particles aro quickly absorbed by the dry atmosphere, and the fibre in process again becomes soft and pliable, following its proper course through the machinery. Where there is no provision for
introducing steam in this manner, it will be convenient to sprinkle water upon the floor, in which case, hot water is best. Care must always be taken not to carry these proceedings to excess, and cause the atmosphere of the room to condense its moisture upon the machinery and walls, giving to everything a damp, clammy feel. Drafts or currents of air should also be carefully avoided, as provocative of the same mischief, whilst good ventilation should be provided. The rooms should also be furnished with sun-blinds to the windows, as excessive heat from direct sun-rays will also produce a similar effect.
As in the management of all machinery, strict supervision should be maintained. Every part should be promptly supplied when broken or worn out, and the small essentials known as "mill furnishings," such as strapping, laces, banding, brushes, oilcans, oil, &c., whilst strictly dealt out, should never be denied in sufficient quantity. Though the aggregate charge resulting from this provision is considerable, economy in this would be at the cost of a more than corresponding depreciation arising from the extra wear and tear of the machinery, leaving out of consideration the inferior quality of the production. Thorough cleanliness should be insisted upon in every department. The machinery should be overhauled and cleansed at stated intervals. The reward for attention to these matters will be a large production, thereby diminishing the cost ; a high quality, which will secure good prices in the market ; a contented class of workpeople, earning good wages, and therefore not ready to quarrel with their employment ; and last, but not least, a satisfactory balance-sheet at stocktaking.
Tow Preparation.—From the moment flax begins to undergo preparation for spinning and weaving, or any other divergent end, there is produced more or less "tow," or short broken fibre. This is principally obtained in the scutching, machining, and dressing processes, to which is generally added the sliver-waste produced in the more advanced processes. That obtained from scutch-mills has usually bad the husk of the plant shaken from it, and is then sent to market as "scutching-tow," commanding only a few shillings a cwt. This is sold to coarse-tow spinners, who usually pass the material through a " shaker," by which it is more perfectly cleansed from the husk, after which, it is put through the "breaker-card." In other cases, it is preferred to get it rescutched over finer and lighter "handles" than those over which the flax was first put. The cost of performing this operation is about 4s. a cwt., whilst the produce obtained will not be more than f of the quantity submitted to the process. Loss of weight and expense of cleaning bring up the cost to something over 1/. a cwt. Sometimes this class of tow is worked alone ; in other cases, it is mixed with " milled tows," or those obtained from the processes of hackling, machining, and dressing in the flax-mill. The tow is first passed through a coarse card, and next through a finisher-card, after which it enters upon its course of preparation for being made into tow-yarn, which does not differ materially from that of line flax.