in botany, the olive-tree: A genus of the monogynia order, belonging to the diandra clas of plants; and in the natural method ranking under the 44th order, Sapiere. The corolla is quadrifid, with the segments nearly ovate. The fruit is a monoporous plum.
There are three species of the olea. 1. The Europea, or common olive-tree, rises with upright solid stems, branching numerously on every side, 20 or 30 feet high; spear-shaped, stiff, opposite leaves, two or three inches long, and half an inch or more broad; and at the axils small clusters of white flowers, succeeded by oval fruit.
This species is the principal sort cultivated for its fruit; the varieties of which are numerous, varying in size, colour, and quality. It is a native of the southern warm parts of Europe, and is cultivated in great quantities in the south of France, Italy, and Portugal, for the fruit to make the olive-oil, which is in so great repute, and is transported to all parts, to the great advantage of those countries where the trees grow in the open ground; the green fruit is also in much esteem for pickling, of which we may see plenty in the shops.
2. The *capensis*, or cape box-leaved olive, rises with shrubby stems, branching numerously from the bottom, six or seven feet high; small, oval, thick, stiff, shining leaves; and at the axillas small clusters of whitish flowers; succeeded by small fruit of inferior value.
3. *Olea odoratissima* (Indian name, *quesa*; Japanese name, *Shio Ran*, it: *Sju Ran*) is thus described by Thunberg, *bulbis fibrosis*, *foliis ensiformibus*, *sefibribus*, *floribus pendulis*. (See Plate CCCXLIX.) The flower of the *olea odoratissima* is by some said to give the fine flavour to the green tea; but Thunberg attributes the said flavour to the *Cemellie seferque*.
Olive-trees are easily propagated by shoots; which, when care has been taken to ingraft them properly, bear fruit in the space of eight or ten years. Those kinds of olive-trees which produce the purest oil, and bear the greatest quantity of fruit, are ingrafted on the stocks of inferior kinds.
Different names are affixed by the French to the different varieties of the olive-tree; and of these they reckon 19, whilst in Florence are cultivated no fewer than 32.
Olive shoots are ingrafted when in flower. If the operation has been delayed, and the tree bears fruit, it is thought sufficient to take off a ring of bark, two fingers breadth in extent, above the highest graft. In that case the branches do not decay the first year; they afford nourishment to the fruit, and are not lopped off till the following spring. Olive-trees are commonly planted in the form of a quincunx, and in rows at a considerable distance from one another. Between the rows it is usual to plant vines, or to sow some kind of grain. It is observed, that olives, like many other fruit-trees, bear well only once in two years. The whole art of dressing these trees consists in removing the superfluous wood; for it is remarked, that trees loaded with too much wood produce neither too much fruit nor of so good a quality.
Their propagation in England is commonly by layers. The laying is performed on the young branches in spring. Give plenty of water all summer, and they will sometimes be rooted and fit for potting off in autumn; but sometimes they require two summers to be rooted effectually: when, however, they are properly rooted, take them off early in autumn, and pot them separately; give water, and place them in the shade till they have taken fresh root; and in October remove them into the greenhouse, &c.
Those you intend to plant in the open ground, as before suggested, should be kept in pots, in order to have occasional shelter of a garden-frame two or three years, till they have acquired some size, and are hardened to the full air; then transplant them into a warm border against a wall; mulch their roots in winter, and mat their tops in frosty weather.
Olives have an acrid, bitter, extremely disagreeable taste: pickled (as we receive them from abroad) they prove less disagreeable. The Lucca olives, which are smaller than the others, have the weakest taste; the Spanish, or larger, the strongest; the Provence, which are of a middling size, are generally the most esteemed.
When olives are intended for preservation, they are gathered before they are ripe. The art of preparing them consists in removing their bitterness, in preserving them green, and in impregnating them with a brine of aromatised sea-salt, which gives them an agreeable taste. For this purpose different methods are employed. Formerly they used a mixture of a pound of quicklime, with five pounds of newly sifted wood-ashes; but of late, instead of the ashes, they employ nothing but a lye. This, it is alleged, softens the olives, makes them more agreeable to the taste, and less hurtful to the constitution. In some parts of Provence, after the olives have lain some time in the brine, they remove them, take out the kernel, and put a caper in its place. These olives they preserve in excellent oil; and when thus prepared, they strongly stimulate the appetite in winter. Olives perfectly ripe are soft and of a dark-red colour. They are then eaten without any preparation, excepting only a seasoning of pepper, salt, and oil; for they are extremely tart, bitter, and corrosive.
The oil is undoubtedly that part of the produce of olive-trees which is of greatest value. The quality of it depends on the nature of the soil where the trees grow, on the kind of olive from which it is expressed, on the care which is taken in the gathering and pressing of the fruit, and likewise on the separation of the part to be extracted. Unripe olives give an intolerable bitterness to the oil; when they are over ripe, the oil has an unguinuous taste: it is therefore of importance to choose the true point of maturity. When the situation is favourable, those species of olives are cultivated which yield fine oils; otherwise, they cultivate such species of trees as bear a great quantity of fruit, and they extract oil from it, for the use of soap-eries, and for lamps.
They gather the olives about the months of November or December. It is best to put them as soon as possible into baskets, or into bags made of wool or hair, and to press them immediately, in order to extract a fine oil. Those who make oil only for soap-eries, let them remain in heaps for some time in their storerooms; when afterwards pressed, they yield a much greater quantity of oil. Those even who extract oil to be used in food, sometimes allow them to ferment in heaps, that they may have more oil; but this is extremely hurtful to the quality of the oil, and is the reason why fine oil is so very rare. M. Duban recommends not to mix found olives with those in which a fermentation has already begun, and still less with such as are putrefied: in both cases, the oil which is extracted is of a bad quality, and unfit for preservation. In order to have the oil in its purity, we must allow it to deposit its sediment, and then pour it off into another vessel. The oil extracted from the pulp only of olives is the most perfect which can be obtained, and will keep for several years; but that which Olive oil is extracted from the kernel only, or from the nut, or from the whole olive ground in the common way in public mills, has always more or fewer defects, loses its limpidity in a certain time, and is very apt to become rancid. Care must be taken likewise to keep the oil in proper vessels well shut. After all, in the course of time, olive-oil loses its qualities, becomes disagreeable to the taste and smell, diminishes in fluidity, and at length thickens considerably.
The refuse of the first pressing, when squeezed a second time, yields an oil, but thicker and less pure than the former. What remains after the second pressing, when mixed with a little water and placed in a pan over the fire, produces by pressure a third oil, but of a very inferior quality. What remains after all the oil is expressed, is termed grignon, and is of no farther use but as fuel.
The sediment, or feces, of new oil, we name after the ancients, amurea; it is an excellent remedy in rheumatic affections. In Paris the wax used for shoes is commonly made of the dregs of defecated oil and smoke-black.
Oil of olives is an ingredient in the composition of a great many balsams, ointments, plasters, mollifying and relaxing liniments. It is of an emollient and solvent nature; mitigates gripes of the colic, and the pains accompanying dysentery; and is one of the best remedies when one has chanced to swallow corrosive poisons; but it by no means prevents the fatal accidents which ensue from the bite of a snake, as has been pretended. It is an effectual cure, as M. Bourgeois tells us, for the sting of wasps, bees, and other insects. A bandage soaked in the oil is immediately applied to the sting, and a cure is obtained without any inflammation or swelling.
Olive oil is of no use in painting, because it never dries completely. The best soap is made of it, mixed with Alicante salt-wort and quicklime.
Great drought, as well as much rain, is extremely injurious to the crop of olives. This fruit is much exposed to the attacks of a worm peculiar to itself, and which injures it so much, that after the olives are gathered the produce of the oil extracted from them is diminished one half.
The wood of the olive tree is beautifully veined, and has a pretty agreeable smell; it is in great esteem with cabinet-makers, on account of the fine polish which it assumes. It is of a resinous nature, and consequently excellent for burning.
As the laurel branch is the symbol of glory, so the olive-branch covered with leaves has from the most ancient times been the emblem of concord, the symbol of friendship and peace.
The leaves of olive-trees have an astringent quality. Many people use them in making gargles for inflammations of the throat.
These plants in this country must be kept principally in pots for moving to the shelter of a greenhouse in winter; for they are too tender to prosper well in the open ground in this climate; though sometimes they are planted against a warm south wall, and sheltered occasionally from frost in winter, by mulching the roots, and matting their tops; whereby they may be preserved, and will sometimes produce fruit for pickling; a very severe winter, however, often kills or greatly injures their young branches; therefore let the principal part be potted in rich earth, and placed among the greenhouse shrubs, and managed as others of that kind.
These trees are often sent over from Italy to the Italian warehouses in London, along with orange-trees, &c., where pretty large plants may be purchased reasonably, which should be managed as directed for orange-trees that are imported from the same country. See Citrus.