considerable damage will be occasioned by it. When they are found to heat too much; that is, when the heat exceeds a moderate glowing warmth, part of the weight by which they are pressed must be taken away; and the cause being removed, the effect will cease. This is called the second, or last, sweating; and, when completed, which it generally will be about the time just mentioned, the leaves may be stripped from the stalks for use. Many, however, omit this last sweating.

When the leaves are stripped from the stalks, they are to be tied up in bunches or hands, and kept in a cellar or other damp place; though if not handled in dry weather, but only during a rainy reason, it is of little consequence in what part of the house or barn they are laid up. At this period the tobacco is thoroughly cured, and as proper for manufacturing as that imported from the colonies.

Tobacco is made up into rolls by the inhabitants of the interior parts of America, by means of a machine called a tobacco wheel. With this machine they spin the leaves after they are cured, into a twist of any size they think fit; and having folded it into rolls of about twenty pounds each, they lay it by for use. In this state it will keep for several years, and be continually improving, as it always grows milder. The Illinois usually form it into carrots; which is done by laying a number of leaves, when cured, on each other, after the ribs have been taken out, and rolling them round with packthread till they become cemented together. These rolls commonly measure about eighteen or twenty inches in length, and nine round in the middle part.

[Bauhin. Long. Lobel. Gregory.

SECTION XII.

Tallow-Tree.

Croton Sebiferum. Tomex Sebifera.-LINN.

Wax-Tree.

Myrica Cerifera.-LINN.

MOST plants produce a certain portion of oil; in some it appears thin and liquid when expressed, as that of the olive and the almond; in others sufficiently thick, and in sufficient abundance for common tallow, as the croton sebiferum, and tomex sebifera, both of which are, in consequence, denominated tallow-tree; and the myrica gale, which secretes it less freely; while the myrica cerifera secretes a still more concrete substance, of the nature of wax rather than of tallow, and which is used in America, where it grows indigenously, for this purpose.

The two first are natives of China; the former a monœcian polyandrian plant, with rhombic-ovate leaves, pointed, very entire, and glabrous; the latter a dodecandrian monogynian plant, with glabrous leaves, and corols without florets; it is about the height of a cherry-tree, its leaves in form of a heart, of a deep shining red colour, and its bark very smooth. Its fruit is enclosed in a kind of pod, or. cover, like a chesnut, and consists of three round white grains, of the size and form of a small nut, each having its peculiar capsule, and within a little stone. This stone is encompassed with a white pulp, which has all the properties of true tallow, both as to consistence, colour, and even smell, and accordingly the Chinese make their candles of it; which would doubtless be as good as those in Europe, if they knew how to purify their vegetable, as well as we do our animal, tallow. All the preparation they give it, is to melt it down, and mix a little oil with it, to make it softer and more pliant. It is true their candles made of it yield a thicker smoke, and a dimmer light than ours; but those defects are owing in a great measure to the wicks, which are not of cotton, but only a little rod of dry light wood covered with the pith of a rush wound

round it; which, being very porous, serves to filtrate the minute parts of the tallow, attracted by the burning stick, which by this means is kept alive.

In like manner the Americans make wax candles of the waxyberry of the myrica cerifera, or candle-berry myrtle, which burn with a fine clear light, for a long time, and possess a fragrant myrtle odour.

We are indebted to Dr. Bostock and Mr. Cadet for a very exact account of its properties and extraction. The myrica cerifera is a shrub which grows abundantly in Louisiana, and other parts of North America. It produces a berry about the size of a peppercorn. A very fertile shrub yields nearly seven pounds. The berries are picked off, thrown into a kettle, and covered with water to the depth of about half a foot. The kettle is then boiled, and the berries stirred and squeezed against the side of the vessel. The wax which they contain is melted out, and swims on the surface. It is skimmed off, passed through a cloth, dried, melted again, and cast into cakes. From the observations of Cadet we learn that the wax forms the outer covering of the berries. The wax thus obtained is of a pale green colour. Its specific gravity is 10150. It melts at the temperature of 109°; when strongly heated it burns with a white flame, produces little smoke, and during the combustion emits an agreeable aromatic odour. Water does not act upon it. Alcohol, when hot, dissolves th of its weight, but lets most of it fall again in cooling.

There is another species of the myrica, M. gale, found in many of the boggy mosses of our own country, that produces the same material. It is also obtained in South America, as we learn from M. Humboldt, from one or two of the palms, and especially the ceroxylon andicola.

There are, also, various other insects, besides the bee, that yield either wax, or a material very nearly resembling it; as the corcus lacca, or gum-lac insect, and perhaps one or two other species of this genus. There is, moreover, another waxy material, collected in a manner somewhat similar, in China, and which is called pela; well known to be the product of an insect, though the name of the insect is not well known.

It is probable, as we have observed already, that in all these cases the matter of wax is obtained by the insect from the vegetable king

dom. And it has been usually supposed that it consists of the pollen which the bees visibly collect on their thighs, and afterwards elaborate in some unknown way. The great difference, however, between wax and this matter which the bees collect has been long remarked. When examined by the microscope, this little mass of pollen is obviously composed of a number of hard grains compressed together; and if it be laid on a hot plate, it does not melt as wax would do, but smokes, dries, and is reduced to a coal; and, if kindled, burns without melting. Some late and very curious experiments, however, of M. Huber, one of the most celebrated apiarists in Europe, have shewn that the pollen has no share whatever in the formation of wax; but that this substance is produced indiscrimi nately from honey, sugar, or any other saccharine matter, which serves as food for the bees. The details of these experiments would occupy too much space: it is sufficient to mention that they were performed by confining separate swarms of bees within their hives, and feeding one hive with honey, another with muscovado sugar, another with treacle, another with refined sugar; in all of which abundance of wax was produced; and, on the other hand, by feeding another hive with only pollen and fruits, no wax whatever was formed, though the bees remained a week in their confinement. Other observations and experiments by this ingenious naturalist still further explain this subject, by shewing what is the real use of the pollen; namely, to afford sustenance for the larve of the bee the moment it is hatched.

There is a vegetable wax which has lately been discovered in the Brazils, though the tree from which it is producd is not accurately known, that bids fair to prove an article of highly-useful and extensive commerce between that country and our own. The only spe

cimen of it which has been received in England, was transmitted to Lord Grenville from Rio de Janeiro, by the Comte de Galveas, as a new article lately brought to that city, from the northernmost parts of the Brazilian dominions, the capiteneas of Rio Grande and Seara, between the latitudes of three and seven degrees north it is said to be the production of a tree of slow growth, called by the natives carnauba, which also produces a gum used as food for men, and another substance employed for fattening poultry.

When the Comte wrote to Lord Grenville in 1809, orders had been sent to the governors of the districts where it grows, requiring

them to report more particularly on the nature and qualities of this interesting tree; we may therefore hope that information will soon be obtained whether the article can be procured in abundance, and at a reasonable price: in which case it will become a valuable addition to the comforts of mankind, by reducing the price and improving the quality of candles, flambeaux, &c.

The article, in the state in which it was sent, resembles much that described by Humboldt, as the produce of the ceroxylon andicola; but it is not likely to be the same, as Humboldt's wax is collected from a stately palm tree, which grows on the high mountains, from 900 to 1450 toises above the level of the sea, and on the edge of the regions of perpetual snow. On the other hand, the Brazilian plant is described as a slow growing tree, but not as a large one, and there are no high mountains delineated in the most accurate and recent maps of the capiteneas where it is found. But a more decisive argument against their identity is the analysis of Vauquelin, published by Humboldt, which shows, that the produce of the ceroxylon consists of two-thirds resin and only one-third wax; but the Brazilian article is entirely wax, and affords not the smallest trace of resin. The Brazilian plant, however, was not entirely unknown to Humboldt, for it appears from his book, that Mr. Correa had informed him, that a palm, called carnauba by the natives of Brazil, produced wax from its leaves.

The wax, in its rough state, is in the form of a coarse pale grey powder, soft to the touch, and mixed with various impurities, consisting chiefly of fibres of the bark of the tree, which, when separated by a sieve, amount to about forty per cent. It possesses the following characters, according to the analysis of Mr. Brande, as given in the Phil. Trans. for 1811.

"It has an agreeable odour, somewhat resembling new hay, but scarcely any taste.

"At 260° Fahrenheit it enters into perfect fusion, and in this state it may be further purified, by passing it through fine linen. By this process, it acquires a dirty green colour, and its peculiar smell becomes more evident. When cold, it is moderately hard and brittle. Its specific gravity is 0.980.

2. "Water exerts no action on the wax, unless boiled with it for some hours; it then acquires a slight brown tinge, and the peculiar odour of the wax.