Page:The American Cyclopædia (1879) Volume XII.djvu/631

 OLIVE 617 the labor is needed to secure the cotton. The olive tree rarely exceeds 20 ft. in height, has lanceolate or lance-oblong leaves, which are pale green above and whitish beneath, and axillary Common Olive (Olea Europaea). clusters of flowers ; from the dull color of the leaves, an olive grove presents a sombre as- pect. The French enumerate over 20 varieties, differing in the size and color of their leaves and fruits. The tree is propagated by various methods ; seedlings are raised upon which to graft the choicer kinds, or these are multiplied by cuttings of the stems and roots, by suckers, by layers, and by protuberances ; the trunks of old trees present numerous swellings or nodules containing undeveloped buds, which are removed and planted like bulbs. The tree is of slow growth, and does not come into bearing until about seven years old; but it continues indefinitely, and there are trees now standing which are supposed to have been in existence before the commencement of the present era. In France the trees are regularly pruned to keep the heads low, in order to fa- cilitate the gathering of the fruit. The wood of the olive is yellowish and very fine-grained, and, especially that of the root, often beauti- fully feathered and clouded ; hence it is valued for small cabinet and inlaid work. The pro- ducts of the tree are the fruit and its oil. The fruit is too bitter to be eaten unless pickled, and in the olive-growing countries large quan- tities are prepared for home use and for ex- port, and some kinds are cultivated especially for their superior fruit ; the different varieties give fruits varying in size from an acorn to a large plum. The fruit is gathered when it has attained its full size, but while still green, and placed in a strong ley of wood ashes or a solu- tion of potash ; when the potash has penetrated to the stone, which is manifested by a change of color, the olives are placed in water, which is renewed several times a day for five days ; a saturated brine is prepared of the purest salt, to which are added coriander, cloves, cinna- mon, and such aromatics as are desired, and boiled a few minutes and strained ; this when cold is mixed with an equal quantity of water and poured over the olives placed in jars or bottles, which are then sealed. Thus prepared, olives are a condiment rather than an article of food, and are much eaten at lunches ; they are thought to improve the flavor of wine as well as to excite an appetite for it ; they are some- times used in salads and to flavor made dishes. Olive oil is obtained from the ripe fruit, which when it has reached that state is of a dark pur- ple color ; the thoroughly ripe olives yield a larger quantity of oil, but not of so fine a qual- ity as oil from those that have just begun to ripen ; the pulp of the fully ripe fruit contains nearly TO per cent, of oil. Those who make the finer kinds of oil gather the fruit by hand as soon as it begins to color, and spread it under sheds, where it is frequently turned and loses the greater part of its contained moisture ; but for common oil the fruit is allowed to lie beneath the trees until it is convenient to gather it, which is sometimes all winter. The process of extracting the oil is essentially the same in different countries. The fruit is crushed to a pulp in a mill, and placed in coarse sacks, which are stacked one upon another and subjected to pressure ; the oil flows into a cistern containing water, from the surface of which it is dipped ; this first pressing is called virgin oil ; a second quality is obtained by mix- ing the contents of the bags with boiling water, replacing them, and submitting them to greater pressure than before. If the fruit is left in heaps until it ferments, it yields a greater quan- tity of oil, but of very poor quality. Oil of the finest quality has a slightly greenish color, a faint but agreeable odor, and a bland taste, leaving a slight sense of acridity in the throat. When it is cooled to nearly the freezing point of water, a solid fat is deposited. If allowed to congeal perfectly, and then subjected to pressure, about one third of fluid oil is sepa- rated, which is oleine and does not congeal at 25 or 20 F. The solid part consists of pal- mitine and similar principles. Olive oil is one of the oils not changed by the action of the air into a resinous substance, and is classed as a non-drying oil. It is sometimes adulterated by the admixture of cheaper oils, and unless the foreign oil be present in considerable amount it is very difficult to detect it; the greater specific gravity of the cheaper oils, as indicated by the elaiometer, is one of the tests ; the chamber of commerce of Nice has recently offered a reward of 15,000 francs for a simple method of detecting adulterations. The production of oil in Italy is estimated at 33,000,000 gallons annually, while that of France is only about 7,000,000. Not many years ago oil was imported almost exclusively in thin, round-bottomed flasks, covered with rush-work, stopped with cotton, and tied over