LIME (O. Eng. lim, Lat. limus, mud, from linere, to smear), the name given to a viscous exudation of the holly-tree, used for snaring birds and known as “bird-lime.” In chemistry, it is the popular name of calcium oxide, CaO, a substance employed in very early times as a component of mortars and cementing materials. It is prepared by the burning of limestone (a process described by Dioscorides and Pliny) in kilns similar to those described under [Cement]. The value and subsequent treatment of the product depend on the purity of the limestone; a pure stone yields a “fat” lime which readily slakes; an impure stone, especially if magnesia be present, yields an almost unslakable “poor” lime. See [Cement], [Concrete] and [Mortar], for details.
Pure calcium oxide “quick-lime,” obtained by heating the pure carbonate, is a white amorphous substance, which can be readily melted and boiled in the electric furnace, cubic and acicular crystals being deposited on cooling the vapour. It combines with water, evolving much heat and crumbling to pieces; this operation is termed “slaking” and the resulting product “slaked lime”; it is chemically equivalent to the conversion of the oxide into hydrate. A solution of the hydrate in water, known as lime-water, has a weakly alkaline reaction; it is employed in the detection of carbonic acid. “Milk of lime” consists of a cream of the hydrate and water. Dry lime has no action upon chlorine, carbon dioxide and sulphur dioxide, although in the presence of water combination ensues.
In medicine lime-water, applied externally, is an astringent and desiccative, and it enters into the preparation of linamentum calcis and carron oil which are employed to heal burns, eczema, &c. Applied internally, lime-water is an antacid; it prevents the curdling of milk in large lumps (hence its prescription for infants); it also acts as a gastric sedative. Calcium phosphate is much employed in treating rickets, and calcium chloride in haemoptysis and haemophylia. It is an antidote for mineral and oxalic acid poisoning.
LIME,[1] or Linden. The lime trees, species of Tilia, are familiar timber trees with sweet-scented, honeyed flowers, which are borne on a common peduncle proceeding from the middle of a long bract. The genus, which gives the name to the natural order Tiliaceae, contains about ten species of trees, natives of the north temperate zone. The general name Tilia europaea, the name given by Linnaeus to the European lime, includes several well-marked sub-species, often regarded as distinct species. These are: (1) the small-leaved lime, T. parvifolia (or T. cordata), probably wild in woods in England and also wild throughout Europe, except in the extreme south-east, and Russian Asia. (2) T. intermedia, the common lime, which is widely planted in Britain but not wild there, has a less northerly distribution than T. cordata, from which it differs in its somewhat larger leaves and downy fruit. (3) The large-leaved lime, T. platyphyllos (or T. grandifolia), occurs only as an introduction in Britain, and is wild in Europe south of Denmark. It differs from the other two limes in its larger leaves, often 4 in. across, which are downy beneath, its downy twigs and its prominently ribbed fruit. The lime sometimes acquires a great size; one is recorded in Norfolk as being 16 yds. in circumference, and Ray mentions one of the same girth. The famous linden tree which gave the town of Neuenstadt in Württemberg the name of “Neuenstadt an der grossen Linden” was 9 ft. in diameter.
The lime is a very favourite tree. It is an object of beauty in the spring when the delicately transparent green leaves are bursting from the protection of the pink and white stipules, which have formed the bud-scales, and retains its fresh green during early summer. Later, the fragrance of its flowers, rich in honey, attracts innumerable bees; in the autumn the foliage becomes a clear yellow but soon falls. Among the many famous avenues of limes may be mentioned that which gave the name to one of the best-known ways in Berlin, “Unter den Linden,” and the avenue at Trinity College, Cambridge.
The economic value of the tree chiefly lies in the inner bark or liber (Lat. for bark), called bast, and the wood. The former was used for paper and mats and for tying garlands by the ancients (Od. i. 38; Pliny xvi. 14. 25, xxiv. 8. 33). Bast mats are now made chiefly in Russia, the bark being cut in long strips, when the liber is easily separable from the corky superficial layer. It is then plaited into mats about 2 yds. square; 14,000,000 come to Britain annually, chiefly from Archangel. The wood is used by carvers, being soft and light, and by architects in framing the models of buildings. Turners use it for light bowls, &c. T. americana (bass-wood) is one of the most common trees in the forests of Canada and extends into the eastern and southern United States. It is sawn into lumber and under the name of white-wood used in the manufacture of wooden ware, cheap furniture, &c., and also for paper pulp (C. S. Sargent, Silva of North America). It was cultivated by Philip Miller at Chelsea in 1752.
The common lime was well known to the ancients. Theophrastus says the leaves are sweet and used for fodder for most kinds of cattle. Pliny alludes to the use of the liber and wood, and describes the tree as growing in the mountain-valleys of Italy (xvi. 30). See also Virg. Geo. i. 173, &c.; Ov. Met. viii. 621, x. 92. Allusion to the lightness of the wood is made in Aristoph. Birds, 1378.
For the sweet lime (Citrus Limetta or Citrus acida) and lime-juice, see [Lemon].