East India GUM is exported to Europe chiefly from Bombay, having been previously conveyed there from the coast of Arabia, and is largely of African origin. Some is also exported from Cal cutta and Bombay by the names of Babul and Ghatti gum, and is of good quality, but is yielded also by Acacia serissa, and by species of other genera.
A gum is also obtained at the Cape from the Acacia karroo, A. horrida, and A. giraffe, and from the A. deeurrens of New Holland.
According to the locality producing it, gum arabic is known as Turkey or Arabic gurn, Barbary or Morocco gum, Senegal, East India, and Cape guni. The mucilage of each of these varieties of gum is employed to give lustre to cmpes and silks, and for cementing into cakes the various pigments used by artists in water colours.
Cherry-tree GUM, including that of peach and apricot trees and other species of Prunus, re sembles inferior gum-arabic in its external cha racters, but is only partially soluble in cold water.
Mastic Resin is produced in Scio from the Pistacia lentiscus, the lentish tree. That which collects on the branches of the trees is called mastic in the tear, and fetches the highest price, while that which falls to the ground constitutes the common mastic. Mastic varnish is well known from its transparency, and its peculiar toughness and tenacity even when spread in the thinnest coat on wood or on canvas. This is due to the presence of a peculiar resin,which does not possess any acid properties.
Olibanum was the frankincense usecl by the ancients in their religious ceremonies. Moses speaks of it in Exodus ; and it long formed a con stituent in the preparation of incense. It is pro duced in India from the Boswellia thurifera, but there are also African and Arabian varieties.
Myrrh.—This gum-resin was an object of trade more than 3500 years ago. It is produced in various parts of Asia and Africa, one myrrh tree bearing the scientific name of Balsamodendron myrrha. Turkey myril is considered the finest, the East Indian being the second in quality. It is employed medicinally as a dentrifrice, and in the preparation of fumigating pastilles.
Tragacanth is gathered in Crete from the Astra gains tragacantha. It is largely employed in calico printing, and has many uses in the arts. •
Catechu is an extract rather than a gum, obtained from the Acacia catechu.
Gambier has similar properties to catechu. It is obtained from the Unc,aria gambier, and both of these are employed in calico printing, dyeing, etc.
Gum Kino of commerce is obtained from Ptero carpus erinaceus and P. marsupium, and Euca lyptus resiuifera. It is used in medicine, and has been proposed to be employed in the arts. The dragon's blood is from P. draco.
Gamboge is obtained in Ceylon, Malabar, Siam, from species of Garcinia. It is much used as a pigment, and in miniatnre painting it is employed to colour varnishes and lacquers.
Elena gum-resin is the product of a tree still undetermined, and although it is of considerable importance, and is imported in large quantities, the locality producing it is not distinctly known. It forms an essential ingredient in many of the finest varnishes.
Copal resin exudes spontaneously from two trees, Rhus copalinnm, and Elseocarpus copalifer, the first being an American and West Indian, and the second an East Indian tree. A variety of copal is obtained from the coasts of Guinea. The American kind comes to Britain in flat fragments, the East Indian in roundish masses, and the latter I furnishes the finest vturnishes. Fresh essence of turpentine dissolves it completely, but old tur pentine will not do so. It is stated that essence of turpentine, digested upon sulphur, will dissolve double its own weight -without lettirig any fall. The oil of rosemary also dissolves copal with great readiness. An excellent varnish may be made by dissolving one part of copal and one of essence of rosemary, with from two to three parts of pure alcohol.
The employment of the gums and resins in the arta has been greatly facilitated by the discovery of new solvents, such as the new alcohols and ethers, naphtha, benzole, chloroform, and others.
Gum-ammoniac.
Ushek, Feshuk, . ARAB. I Samugh b' sherin, PERS. Astruck, . . HIND. IThiS a bitter, nauseous, bad-smelling gum resin, and used in medicine. Dorema ammoniactun, Fernla ammonifera, Fee, F. orientalis, and F. Persica, have all been named as its source.