The colophonia of the ancients was a liquid resin, named from town of Ionia, in Asia Minor, whence it was brought and left for a year, after which they are felled, and the roots and the branches of the trees cut into billets, split, and piled in a kiln, and covered with turf; or they are placed in a conical cavity dug in the ground, and piled up in large stacks, which are covered with turf, with spaces left for air to pass, to keep up combustion. Fire is then applied to the top of the pile, and it is suffered to burn downwards with a slow smothered flame, which continues, for ten or twelve days: during this time the tar is formed by the decomposition of the resinous juice; it flows to the bottom, and runs out, through a small channel cut for the purpose, into barrels. The stacks are generally built on the slope of a hill, so that the tar can be easily collected, and put into barrels; in which state it is brought to this country.

Pitch is condensed tar, procured by evaporation-five barrels of tar yield two barrels of pitch.

Both are compounds of resin, empyreumatic oil, pyro-1 igneous acid, and charcoal.

2. Pinus Larix.i

Officinal, a. Resina liquida, vulgo. Terebinthina Veneta, Edin. Resina liquida, Dub.

β. Pini Oleum volatile, Edin. Venice Turpentine; Oil of Turpentine.

Syn. Terebinthe de Venise (F.), Venetischer Terbenthin (G.), Trementina Veneta (I.).

There are two varieties of the larch tree, one of them a native of America, the other of the South of Europe and Siberia. It rises erect to the height of fifty feet in northern climates, but in the South it rises upwards of 100 feet, sending off slender, spreading branches, which droop at their extremities. The leaves are deciduous, soft, and of a bright-green colour; in tufts, generally containing forty or more, springing from short, thick, corrugated sheaths, and spreading like a painter's brush; linear, somewhat obtuse, and entire: the male flowers, which appear in April, are in small, lateral, cylindrical catkins, with the apexes of the anthers inflated; the female are in erect, ovate catkins, twice as large as the male, and in some instances purple at the top : the strobiles or cones are about an inch long, obtuse, and purplish at the apex, with the scales smooth on the surface, lacerated at the edges, and concealing under each two winged seeds.

Theophrasti. Larchenbaum (G.), Lorkenboom (Dutch), Lerketrae (Dan.), Meleze (F.), Larice (I. S.) Larico (Port.), Listweniza (Russ.). The larch tree has been cultivated in England since 1629,-Hart. Keu.

The larch tree grows to very great perfection in the forests of Baye in Provence, where a very large proportion of the Venice turpentine of commerce is procured. It is obtained by boring a hole with an auger into the heart of the tree, at about two feet from the ground, and fitting into it a small pipe, through which the turpentine flows slowly into vessels placed for its reception. This process is begun in May, and continued till September; when the different quantities collected are put together, and purified by straining through cloths or hair sieves. No trees under twelve inches in diameter are tapped; but vigorous trees will yield, annually, seven or eight pounds for forty or fifty successive years, or during the term of their life.1 Much of the Venice turpentine of the shops is brought from America, and is perhaps procured from a different species of fir.

The volatile oil is separated from it by distillation in the same manner as from the common turpentine.

3. Pinus Balsamea.2

Officinal. Terebinthina Canadensis, Lond. Resina liquida, Dub. Canada Turpentine. Canada Balsam. Syn. Baume de Canada (F.), Kanadischer balsam (G.).

This tree is a native of the coldest regions in North America, flowering in May. It is a straight, elegant tree, rarely exceeding 40 feet in height, and 12 or 15 inches in diameter, covered with a smooth whitish-grey bark. The leaves are in double rows, like a comb, short, not exceeding 8 lines in length, and linear, but broader than the former two species, and less pointed, of a bright green colour on the upper surface, marked with whitish lines underneath, and fragrant: the cones, which ripen in October, stand erect on the branches, are large, nearly cylindrical, of a beautiful, deep, glossy, purple colour, inclining to black; and exude a great quantity of transparent resin, which gives them a very rich, beautiful appearance.

The manner in which the Canada balsam, or fine turpentine, yielded by this tree, is collected, is by incisions into the body of the tree from which it exudes, and breaking the vesicles which form spontaneously on the tree. These vesicles exist in great quantity between the wood and the bark. Canada balsam is brought to this country in casks, each containing about one hundred weight.

1 Besides turpentine, the larch tree exudes a species of manna, which is named Briancon manna. It is in little white concrete drops, which adhere to the leaves, and tastes sweet like new honey; but it has the flavour of turpentine, which it contains. The inner part of the tree yields also a gum similar in its properties to •acacia gum, of a reddish colour, with a slight resinous taste, and is perfectly soluble in water. In Russia it is officinal, and sold, as Pallas observes, under the improper name of Orenberg gum, being obtained from the Uralian Forest.- Flora Rossica, i. pp. 2, 3.

2 Balsamtanne (G.), Le beaumierde Gilead (F.).

4. Pinus Abies.1

Officinal, a. Abietis resina, Lond. Resin of the Spruce Fir. β. PIX Abietina, Lond. Resina sponte concreta, vulgo. PIX Burgundica, Edin. Resina. Thus. Pix Burgundica, Dub. Burgundy Pitch.

The Norway spruce fir is a native of Europe, and of the moist parts of Northern Asia, flowering in April. It is a lofty, noble tree, rising from 150 to 200 feet in height, and from three to five feet in diameter; it is straight, pyramidal, and covered with a reddish scaly bark. The leaves are short, thickly set upon the branches, slightly carinated on both sides, of a dusky green colour, shining on the upper surface, and often curved: the male catkins are ovate, purplish, and scattered in the axils of the leaves; the female are also purple, and generally terminal; the strobiles or cones are long, nearly cylindrical, greenish before they are ripe, but afterwards purple, and always pendent; the scales, which are arranged in eight spiral rows, have an oval shape terminating in a point, and become ragged at the edges.2

The Resin or Thus of the old London Pharmacopoeia exudes spontaneously from the bark of the Norway spruce fir, and concretes as it exudes. It undergoes no preparation, but is brought to us in the form of tears or small masses, packed in casks, each containing from one to two hundred weight. The greater part comes from Germany; but a small quantity of a purer description comes from France.