With leaves of small growth, one passage through the machine will ordinarily suffice, but it is advisable to pass leaves of luxuriant growth through a second time; they may now be passed through in bundles of 2-3, as the pressure is then more effective, and is less liable to damage the fibre. Between the first and second passages, the leaves must be well washed, and not allowed to lie Mug, otherwise the fibres will be stained. Immediately after leaving the crushing-machine, the leaves must be thoroughly washed, squeezed by the machine hereafter described, and then taken to the scraping-machine.
This is illustrated in Fig. 627. It consists of an iron drum, revolving at a high speed between two iron frames, the whole being covered in with a sheet-iron casing. At each side of the framing, is an opening for the admission and exit of the fibre. Inside the casing, are two curved wooden shields, whieh, by means of two levers b, and two treadles c, are brought nearer to or removed farther from the periphery of the drum. The levers actuate the upper, whilst tho treadles act on the lower, ends of the two shields. Their position can thus he regulated, according to the work to be done. When used as a seraping-machine, the periphery of the drum is fur nished with a series of hard wood scrapers, or blades, fixed iu holders with a pack iog of indiarubber, in order to render elastic the blows of the blades on the fibre. The machine is made wide enough for two mon to work at the same time. They stand in front of the machine, one inserting fibre through the opening on his right, the other through the opening on his left. The workman introduces the leaves through one of the side openings, allowing them to rest on one of the curved shields or aprons ; ho then fastens the other ends of the leaves, by twisting them round one of the two hooks d. In order to scrape the leaves, he raises one of the lovers b, which has the effect of bringing one of the curved shields, and with it the leaves, up to the scraping-blades, which, revolving at a high speed, strike the leaves gently but effectually, and remove all their non-fibrous parts. When the upper part of the exposed leaves has been well scraped, one of the treadles c is depressed, which brings tip the lower part of the shield, and thus exposes the ends of the leaves to the action of the blades.
When the scraping is complete, the lever and treadle are released, the le wes are withdrawn, and their position in the machine is reversed, the part already scraped being now twisted round one of the hooks d. By a little manipulation, every part of the leaf is fully exposed to the action of the blades, and thoroughly scraped. When used as a scraping-machine, an arrangement is applied inside the frame, by which the refuse material 6craped from the leaves flies off the blades on to the ground beneath and in rear of the machine. With some leaf fibres, scraping is unnecessary. If the outer skin of the leaf is soft and tender, and if the non-fibrous part is mostly juice, crushing, washing, and squeezing suffice to extract the fibre from the leaf ; any small non-fibrous particles which cling to the fibres, even after washing and drying, are effectually removed by brushing.
After leaving the scraping-machine, the fibre is again washed, 2-3 times, according to the growth of the leaf, the state of the fibre, the supply of water, and the cost of labour ; the more thorough the washing, the better the colour of the fibre will be. The washing is best carried out in shallow troughs, or in a stream having a depth of 12-24 in. A supply of clean running water is of very great importance. The fibre is held by one hand, and violently agitated in the water, whilst the other hand removes any leaf still adhering to it ; a small wooden blade, about 12 in. long, much facilitates the operation. Several machines have been constructed to wash the fibre mechanically ; but their use is attended with certain evils and expenses. As a rule, where the agave and kindred plants grow, labour is cheap, and therefore it is better and more practical to wash the fibre by band. An additional advantage which hand-washing presents over machine-washing is the fact that some leaves need much less washing than others. In machine-washing, all leaves must be washed alike.
Between the washings, the leaves or fibre should be passed through the squeezing-machine, shown in Fig. 628. It is constructed like an ordinary mangle or wringing-machine ; the rollers are very strong, the top one a being convex, and the bottom one 1) concave, so that the expressed juice and water have a tendency to flow towards, and to drop off, the middle of the rollers.