Boiling.—This is a most important operation. By it the gluten and coloring matter are separated from the fibres, which separation is absolutely necessary, in order to prepare the fibre to receive the bleaching. It is necessary to observe that the three several sorts of layers which are found in the tree, and which, under the head of "crushing," are recommended to be pressed separately, should be also boiled separately, because the outermost layer has more coloring matter than the next under it, which again has more than the innermost layer. As they are boiled so will they be dried and shipped, and each sort will have a different price in the market; that fibre which is lightest in color bearing the preference, in consequence of its not requiring more than six hours to bleach—whilst the darkest will, probably from its greater tenacity, take twelve to eighteen hours. It is advisable to place over each boiler the means of lifting the mass of fibre when boiled, and suffering it to drain into the boiler before it is carried away to be washed. This is easily effected by a chain from the roof, to which may be hung a lever, having at that end over the boiler some hooks attached to it, whereby the mass is lifted out of the boiler, and the liquor thus preserved for the next boiling.
Washing.—It is absolutely necessary that the fibre should be well washed after being taken out of the boiler, in order that all extraneous matter may be separated therefrom. In choosing the site for an establishment of this kind, care must always be taken to make choice of a spot in the immediate neighbourhood of a large river, or other plentiful supply of fresh clean water. The machinery necessary for cleansing and washing the fibre may be of various descriptions; but, perhaps a selection from one of the three following sorts will be found to answer every purpose, viz., those used by paper manufacturers in England, and by coffee planters and arrowroot growers in the West Indies.
Drying.—The washed fibre, when hung over lines made of the twisted fibre, or any other convenient material, will be sufficiently dry in a few hours to be taken down, when more can be hung up, and then several batches can be dried in a day; and it will be necessary to have the drying ground as near the water as possible, in order to save weight in carriage.
Pressing.—When the fibre is perfectly dry, it must be well pressed, for the convenience of packing, carriage, and shipment. The hydraulic press is the best machine that can be used for the purpose; but in the absence of that, the lever and screw will make a large amount of pressure available. A hydraulic press of from 400 to 500 tons, will press bales of from four to five hundred weight each, which will not be too large for shipment."
STARCH-PRODUCING PLANTS INVESTIGATED.
Starch is one of the constituent parts in all mealy farinaceous seeds, fruits, roots, and other parts of plants, and is in large demand for domestic use, the arts, &c. Our common starch is made from wheat, and a good deal from potatoes. Pure fecula is separated by art from a variety of plants.
Of plants yielding starch we have the Indian arrowroot, which is the fecula in the rhizomata of several species of the Marantaceæ. In the West Indies it is obtained from the Maranta arundinacea, Allomyca and nobilis, and also from various species of Canna called Tous les mois, and in the East Indies from species of Curcuma, and from Maranta ramossissima in Silhet.
The bread fruit (Artocarpus incisa), already alluded to, yields a large quantity of starch; as do the sweet potato (Convolvulus Batatas, or Batatas edulis). The pith or farinaceous part of the trunk of the Caryota urens, is almost equal to the finest sago. In Assam the sago of this palm is much used.
The two varieties of the Cassava afford a very superior fecula, which is imported under the name of Brazilian arrowroot. 8,354 bags of tapioca and farina were imported from Maranham in 1834. Some excellent starch from Norfolk Island was shown at the Great Exhibition.
The Cycadaceous family yields much starchy matter, along with mucilage. From the soft stems of Cycas revoluta and C. circinalis, natives of China and the East Indies, a kind of sago is made. These plants are propagated by suckers. Zamia pumila, a native of the Cape of Good Hope, and other species of this remarkable genus of plants, which is nearly related to both ferns and palms, supply an amylaceous matter, which has been sold as arrowroot. A similar product is obtained from Alstrœmeria pallida, a perennial plant, with pink red flowers, growing in Chili. From the nuts of the Cycas circinalis, the Singalese prepare an inferior kind of starch, by pounding the fresh kernels. These are cut in slices, and well dried in the sun before they are fit for use, otherwise when eaten they are intoxicating, and occasion vomiting and purging.