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color and the double height of the vegetation. But, in order to convince oneself in silviculture that such or such a manure or substance acts favorably or otherwise, study for whole years, and application of the system to a very large extent of land, were indispensable. After five years' steady devotion to this specially, M. Chevandier communicated the substance of his discoveries to the academy. He commenced his experiments by choosing, among the substances that cheapness rendered accessible, such as could restore to the soil the elements of the azote or salt withdrawn from it for the support of the forest. As sources of azote, he employed the salts of ammonium; as sources of mineral substances, he used wood ashes, which contain the whole mineral portion of the wood before its combustion. He also tried lime, the salts of potash and of soda, the phosphate of bone-lime, plaster, and the sulphate of iron; and earthy substances, the residue of factories, of salts of potash and soda, (oxy sulphuret of calcium,) which had already been, and with advantage, tried in the valleys of the Vosges. It would be impossible to transcribe the tabular view drawn up by M. Chevandier, which gives the individual history and the bill of health of 5,530 subjects-pines, cedars, oaks, beeches, larches, &c., &c. I have only room for the general conclusions, which may be divided into four categories:
1st. Substances whose fertilizing action was more or less marked. These were the oxy-sulphuret of calcium, the chlorohydrate of ammonia, plaster of Paris, wood ashes, sulphate of ammonia, lime, non-calcined bones, and proudrette.
2d. Substances whose fertilizing effect was slightly marked or doubtful. These were the carbonate of potash, coagulated blood, calcined bones, an equal mixture of nitrate of potash, non-calcined bones, sulphate of iron, and carbonate of lime, and an equal mixture of nitrate of potash and non-calcined bones.
3d. Substances which seemed to have no effect at all-the carbonate of soda, the nitrate of potash, and sea salt.
4th. Substances which seemed to have had an injurious effect-the sulphate of iron, and equal mixtures of sulphate of iron with lime, or of sulphate of iron with carbonate of lime.
The residuum of soda and potash works, known by the name of the oxy-sulphuret of calcium, generally supposed to be utterly useless, has been proved by M. Chevandier's experiments to be the most wonderful substance ever employed for fertilizing purposes. It augments the growth of forests over 100 per cent. In the neighborhood of soda works there are huge piles of it, the accumulation of years. At Marseilles it is thrown into the sea, while there are, throughout the department, vast pine plantations upon which it might be applied with great advantage.
ON THE TALLOW TREE.
[Communicated by the author in a letter from Ningpo, China, to the Commissioner of Patents.] Uses of the Stillingia Sebifera, or Tallow Tree, with a notice of the Pe-la, or Insect-wax, of China. By D. J. Macgowan, M. D., Corresponding Member of the Agricultural and Horticultural Society of India.
The botanical characters of this member of the Euphorbiaceae are too well known to require description, but hitherto no accurate account has
been published of its varied uses; and, although it has become a common tree in some parts of India and America, its value is appreciated only in China, where alone its products are properly elaborated.
In the American Encyclopædia, it is stated that this tree is almost naturalized in the maritime parts of South Carolina, and that its capsules and seeds are crushed together and boiled, the fatty matter being skimmed as it rises, hardening when cool.
Dr. Roxburgh, in his excellent Flora Indica, says: "It is now very common about Calcutta, where, in the course of a few years, it has become one of the most common trees. It is in flower and fruit most part of the year. In Bengal it is only considered an ornamental tree. The sebaceous produce of its seeds is not in sufficient quantity, nor its quality so valuable as to render it an object worthy of cultivation. It is only in very cold weather that this substance becomes firm; at all other times it is in a thick, brownish, fluid state, and soon becomes. rancid. Such is my opinion of the famous vegetable tallow of China."
Dr. Roxburgh was evidently misled in his experiments by pursuing a course similar to that which is described in the Encyclopædia Americana, (and in many other works,) or he would have formed a very different opinion of this curious material. Analytical chemistry shows animal tallow to consist of two proximate principles-stearine and elaine. Now, what renders the fruit of this tree peculiarly interesting is the fact that both these principles exist in it separately in nearly a pure state. By the above-named process, stearine and elaine are obtained in a mixed state, and consequently present the appearance described by Roxburgh. Nor is the tree prized merely for the stearine and elaine it yields, though these products constitute its chief value; its leaves are employed as a black dye; its wood, being hard and durable, may be easily used for printing-blocks and various other articles; and, finally, the refuse of the nut is employed as fuel and manure.
The Stillingia sebifera is chiefly cultivated in the provinces of Kiangsi, Kongnain, and Chehkiang. In some districts near Hangchan, the inhabitants defray all their taxes with its produce. It grows alike on low alluvial plains and on granite hills, on the rich mould at the margin of canals and on the sandy sea-beach. The sandy estuary of Hangchan yields little else. Some of the trees at this place are known to be several hundred years old, and, though prostrated, still send forth branches and bear fruit. Some are made to fall over rivulets, forming convenient bridges. They are seldom planted where anything else can be conveniently cultivated-in detached places, in corners about houses, roads, canals, and fields. Grafting is performed at the close of March or early in April, when the trees are about three inches in diameter, and also when they attain their growth. The Fragrant Herbal recommends for trial the practice of an old gardener, who, instead of grafting, preferred breaking the small branches and twigs, taking care not to tear or wound the bark.
In mid-winter, when the nuts are ripe, they are cut off with their twigs by a sharp crescentric knife, attached to the extremity of a long pole, which is held in the hand and pushed upwards against the twigs, removing at the same time such as are fruitless. The capsules are gently pounded in a mortar to loosen the seeds from their shells, from which they are separated by sifting. To facilitate the separation of the
white sebaceous matter enveloping the seeds, they are steamed in tubs, having convex open wicker bottoms, placed over caldrons of boiling water. When thoroughly heated, they are reduced to a mash in the mortar, and thence transferred to bamboo sieves, kept at a uniform temperature over hot ashes. A single operation does not suffice to deprive them of all their tallow; the steaming and sifting are therefore repeated. The article thus procured becomes a solid mass on falling through the sieve; and, to purify it, it is melted and formed into cakes for the press. These receive their form in bamboo hoops, a foot in diameter and three inches deep, which are laid on the ground over a little straw. On being filled with the hot liquid, the ends of the straw beneath are drawn up and spread over the top, and, when of sufficient consistence,. are placed with their rings in the press. This apparatus, which is of the rudest description, is constructed of two large beams placed horizontally, so as to form a trough capable of containing about fifty of the rings with their sebaceous cakes; at one end it is closed, and at the other it is adapted for receiving wedges, which are successively driven into it by ponderous sledge-hammers wielded by athletic men. The tallow oozes, in a melted state, into a receptacle below, where it cools. It is again melted and poured into tubs smeared with mud to prevent its adhering. It is now marketable, in masses of about eighty pounds each, hard, brittle, white, opaque, tasteless, and without the odor of animal tallow. Under high pressure it scarcely stains bibulous paper; melts at 104° Fahrenheit. It may be regarded as nearly pure stearine; the slight difference is doubtless owing to the admixture of oil expressed from the seed in the process just described. The seeds yield about eight per cent. of tallow, which sells for about five cents per pound.
The process for pressing the oil, which is carried on at the same time, remains to be noticed; it is contained in the kernel of the nut, the sebaceous matter, which lies between the shell and the husk, having been removed in the manner described. The kernel, and the husk covering it, is ground between two stones, which are heated to prevent clogging from the sebaceous matter still adhering. The mass is then placed in a winnowing machine precisely like those in use in western countries. The chaff being separated, exposes the white oleaginous kernels, which, after being steamed, are placed in a mill to be mashed. This machine is formed of a circular stone groove, twelve feet in diameter, three inches deep, and about as many wide, into which a thick solid stone wheel, eight feet in diameter, tapering at the edge, is made to revolve perpendicularly by an ox harnessed to the outer end of its axle, the inner turning on a pivot in the centre of the machine. Under this ponderous weight the seeds are reduced to a mealy state, steamed in the tubs, formed into cakes, and pressed by wedges in the manner above described; the process of mashing, steaming, and pressing being repeated with the kernels likewise.
The kernels yield above thirty per cent. of oil. It is called ising-yu, sells for about three cents per pound, answers well for lamps, though inferior for this purpose to some other vegetable oils in use. It is also
employed for various purposes in the arts, and has a place in the Chinese Pharmacopoeia, because of its quality of changing gray hair black, and other imaginary virtues. The husk which envelopes the kernel, and the shell which encloses them and their sebaceous covering, are
used to feed the furnaces, scarcely any other fuel being needed for this purpose. The residuary tallow-cakes are also employed for fuel, as a small quantity of it remains ignited a whole day. It is in great demand for chafing-dishes during the cold season, and, finally, the cakes which remain after the oil has been pressed out are much valued as a manure, particularly for tobacco fields, the soil of which is rapidly impoverished by the Virginian weed.
Artificial illumination in China is generally procured by vegetable oils; but candles are also employed by those who can afford it, and for lanterns. In religious ceremonies no other material is used. As no one ventures out after dark without a lantern, and as the gods cannot be acceptably worshipped without candles, the quantity consumed is very great. With an unimportant exception, the candles are always made of what I beg to designate as vegetable stearine.
When the candles, which are made by dipping, are of the required diameter, they receive a final dip into a mixture of the same material and insect-wax, by which their consistency is preserved in the hottest weather. They are generally colored red, which is done by throwing a minute quantity of alkanet-root (Anchusa tinctoria, brought from Shangtung) into the mixture. Verdigris is sometimes employed to dye them green. The wicks are made of rush, coiled round a stem of coarse grass, the lower part of which is slit to receive the pim of the candlestick, which is more economical than if put into a socket. Tested in the mode recommended by Count Rumford, these candles compare favorably with those made from spermaceti, but not when the clumsy wick of the Chinese is employed. Stearine candles cost about eight cents the pound.
Prior to the thirteenth century, beeswax was employed as a coating. for candles; but about that period the white-wax insect was discovered; since which time that article has been wholly superseded by the more costly but incomparably superior product of this insect. It has been described by Abbé Grossier, Sir George Staunton, and others; but those accounts differ so widely amongst themselves, as well as from that given by native authors, as to render further inquiry desirable. From the description given by Grossier, entomologists have supposed the insect which yields the pe-la, or white wax, to be a species of coccus. Staunton, on the contrary, describes it as a species of cicada (Flata limbata.) As described by Chinese writers, however, it is evidently an apterous insect; hence the inference either that there are two distinct species which produce white wax, or that the insect Staunton saw was falsely represented as the elaborator of this beautiful material.* This, like many other interesting questions in the natural history of this portion of the globe, must remain unsolved until restrictions on
*A few particulars regarding the Himalayah wax-insect, (Flata limbata,) by Capt. Hutton, are published in the Journal of the Asiatic Society of Bengal, vol. xii. After alluding to Sir George Staunton's and the Abbe Grossier's account of the wax-yielding insect of China, and to various authorities, Captain Hutton observes: "From all these statements, therefore, we arrive at the positive conclusion, that, as this depesitc (the deposite of F. limbata) will neither melt on the fire per se, nor combine with oil, it cannot be the substance from which the famous white wax of China is formed; and we are led to perceive, from the difference in the habits of the larva of Flata limbata, and that of the insect mentioned by the Abbé Grossier, that the wax is rather the produce of a species of coccus than of the larva of F. limbata, or even of the allied F. nigricornis."
foreign intercourse are greatly relaxed, or wholly removed. In the mean time, native writers may be consulted with advantage. It is from the chief of these-the Puntsau and the Kiangfangpu, two herbals of high authority-the subjoined account has been principally derived.
The animal feeds on an evergreen shrub or tree-Ligustrum lucidum-which is found throughout Central China, from the Pacific to Thibet; but the insect chiefly abounds in the province of Sychuen. It is met with, also, in Bunan, Hunan, and Hupeh. A small quantity is produced in Kinhwa, Chehkiang province, of a superior description. Much attention is paid to the cultivation of this tree; extensive districts of country are covered with it; and it forms an important branch of agricultural industry. In planting they are arranged like the mulberry, in rows about twelve feet apart; both seeds and cuttings are employed. If the former, they are soaked in water in which unhusked rice has been washed, and their shells pounded off. When propagated by cuttings, branches an inch in diameter are recommended as the most suitable size. The ground is ploughed semi-annually, and kept perfectly free from weeds. In the third or fourth year they are stocked with the insect. After the wax, or insect, has been gathered from the young trees, they are cut down just below the lower branches, about four feet from the ground, and well manured. The branches which sprout the following season are thinned, and made to grow in nearly a perpendicular direction. The process of cutting the trunk within a short distance of the ground is repeated every four or five years, and, as a general rule, they are not stocked until the second year after this operation. Sometimes the husbandman finds a tree which the insects themselves have attained; but the usual practice is to stock them, which is effected in spring with the nests of the insects. These are about the size of a "fowl's head," and are removed by cutting off a portion of the branch to which they are attached, leaving an inch each side of the nest. The sticks, with the adhering nests, are soaked in unhusked rice-water for a quarter of an hour, when they may be separated. When the weather is damp or cool, they may be preserved in jars for a week; but if warm, they are to be tied to the branches of the trees, to be stocked without delay, being first folded between leaves. By some the nests are probed out of their seat in the bark of the tree, without removing the branches. At this period they are particularly exposed to the attacks of birds, and require watching. In a few days after being tied to the tree, the nests swell, and innumerable white insects, the size of "nits," emerge, and spread themselves on the branches of the tree; but soon, with one accord, descend towards the ground, where, if they find any grass, they take up their quarters. To prevent this, the ground is kept quite bare; care being taken also that their implacable enemies, the ants, have no access to the tree. Finding no congenial resting place below, they re-ascend, and fix themselves to the lower surface of the leaves, where they remain several days, when they repair to the branches, perforating the bark to feed on the fluid within.
From "nits" they attain the size of "Pediculus homi.' Having compared them to this, the most familiar to them of all insects, our authors
*The Himalayah insect is not confined to a ligustrum.