Oak, or Quercus, L . a genus of plants, consisting of 29 species, two of which, according to Dr. Withering, are indigenous. The principal of these is the Robur, or Common Oak, found in various parts of Britain, where it flowers in the month of April.

The oak thrives better in hilly than in boggy ground, but flourishes most luxuriantly oh rich black soils, or in strong moist loams; and, while it is young, in large plantations. It is propagated generally by sowing acorns in the proportion of from four to six bushels per acre, together with some white -thorn berries, and seeds of furze or whins; both to shelter the young plants from the severity of the cold winds, and also to protect them from being devoured by hares, rabbits. etc. As they advance in size, the stronger saplins should be selected to stand, while the more weakly are occasionally cut down ; because the roots of the oak strike deeply into the ground, and the tree will not always grow with equal energy, if it be removed from its primitive soil. Nevertheless, very young oaks may be transplanted two, and even three times, provided the tap or principal root be cut off at every removal; though, such trees will be neither so full at heart, compact, and strong, nor so lasting as those which are suffered to stand on the spot where the seed was originally deposited.

This tree is remarkable for the slowness of its growth, its great bulk, and longevity. It has been observed, that the trunk attains, in general, only fourteen inches, in diameter, in the course of eighty years. But, after arriving at a certain age, its bulk rapidly increases : thus, the trunk of an oak, belonging to Lord POWIS , and growing in Bromfield wood, near Ludlow, in Shropshire, measured in 1764, sixty-eight feet in girth, and twenty-three feet in length; containing in the whole 1455 feet of timber, round measure, or twenty-nine loads and five feet, each load consisting of 50 feet. And Dr. Darwin mentions the Swilcar Oak, a very large tree growing in Needwood forest, which measures thirteen yards in circumference at its base, eleven yards round, at the height of four feet from the earth, and which is believed to be six hundred years old.

The oak is one of the most valuable and majestic trees : its leaves are eaten by horses, cows, goats, and sheep;- deer and swine fatten on the acorns. Its bark, when stripped off, is usefully employed for tanning leather, and afterwards for hot -beds and fuel. It should not, however, exceed the age of 40 or 50 year's, as after that time it becomes corky, and does not answer, the purpose of the tanner.

Oak - timber is well adapted to almost every purpose of rural and domestic economy, particularly for staves, laths, and spokes of wheels. Being hard, tough, tolerably flexible, and not very liable to splinter, it is generally preferred to all other timber for building ships of war ; especially if the tree be suffered to stand for three or four years after it has been larked : because it thus becomes perfectly dry, and the inspissated sap renders it much stronger than the heart of any other oak-tree, which has not been stripped ; so that the. timber acquires greater strength, weight, hardness, and durability.

As this tree is of such eminent utility in naval architecture, and cannot be lent without great difficulty, Mr. Randall, of Maidstone, in Kent, proposed, in 1795, to the Society for the Encourage ment of Arts, etc. a method of training oaks to compass-shapes, for the purpose of ship-building. His plan consists in reversing the pract ice usually followed, in order to obtain strait-stemmed trees ; by taking off, every year, in the months of March and June, all the lateral shoots closely to the stem, commencing when the tree is about eight feet high, and continuing the operation every year, till it has attained the height of 20 feet. In consequence of this management, the oak grows somewhat crooked, and the curvature will increase as the tree advances in years.

This part of his plan, Mr. Randall considers to be particularly applicable to parks, hedge-rows, open plantations. The other part of his suggestion relates to forests, in which the underwood is regularly cut every fifteenth or twentieth year, and where many clean and thriving young oaks are often discovered. If two of these grow so near as to reach each other by inflexion, he proposes to bend down their heads, by means of a hooked stick, and to join them together, by interweaving their respective branches; in consequence of which, the trees will assume a direction that will greatly facilitate the future labour of the shipbuilder. The proper time for performing these operations is from the age of eight to fourteen years, if the oaks grow freely; and the most convenient season for interweaving the branches, is in the spring, before the leaf appears.Although we cannot enter into farther details, relative to this method of promoting the growth of compass-timber, yet we trust the plan is sufficiently obvious and practicable, to be generally adopted : the curious reader is therefore referred to the 13th vol. of the Transactions of the patriotic Society above mentioned.

The saw-dust, and even the leaves, though inferior to the bark, have been found useful in tanning. It appears, from numerous experiments made by the Rev. Mr. Swayne, of Puckle-church, near Bristol, and recorded in the 10th vol. of the Transactions of the Society for the Encouragement of Arts, etc. that half a peck of oak-leaves contains nearly as much astringent matter as one pound of bark.- Farther, the leaves make excellent hot-beds, and the sawdust is the principal indigenous vegetable used in this country, for tinging fustians of various brown colours.

The galls, or excrescences, produced on the leaves, are employed for dyeing, and various other purposes, already stated in p. 355, of our 2d volume.- The balls, or apples, growing on this tree, are sometimes substituted for the galls, in dyeing black colours, with the addition of copperas; but these shades, though more beautiful, are by no means.of equal durability to those obtained from the former.- Lastly, the juice, expressed from oak-apples, when mixed with vitriol and gum arabic, will ke an excellent black ink.

With respect to the medicinal properties of the oak, its bark is a -powerful astringent, whence it has often been used with advantage in haemorrhages, alvine fluxes, and other immoderate secretions. i Beside the common oak, so generally known and cultivated, there is an exotic species,which has late-ly been recommendeds, to public at--tention by Mr. Charles White, in the 5th vol. of the MifmoirS-of the Literary and Philosophical. So-ciety of Manchester. This species is there called the Iron,Wainscot, or Turkey Oak, -and is stated to be a non-descript variety or the Quer-cus Cerris, or smaller prickly-cup-ped Spanish Oak, or that which Mr. Aiton (in his Hortus Kew-msisj, terms the frondosa.— The Iron Oak grows to a considerable height, producing a bulky trunk, and widely spreading head, with large oblong-oval, deeply-serrated leaves, and acorns of an unusual size, in capacious prickly cups :-from these circumstances, we believe it rather to. be the species denominated Aegilops. or Large Prickly-cuppedSpaniihOak^ which grows not only in Spain,.but-also in Turkey (whence the Iron kind was originally brought to England), and corresponds in every other respect to the Iron-or Wainscot Oak.

This valuable species is propagated, in a similar manner with the common British Oak, which it fully equals in hardness, and weight, while it excels in growth or size, as will appear from the following comparative statement: .

Height. Girth.

feet. In. feet. in.

An Iron Oak, 20 years old, measured - 36" 0 — 3 3 '

Another of the same age - - - 37 O — 30

An English Oak, 20 years old' - - 2S O — 2 6

Another 40 years of age - - 39 O — 2 10

T3 our

Our limits will not permit us to enter into an analysis of Mr. White's Memoir ; we shall, therefore, only observe that the species now recommended, will thrive much faster than the common Oak in a similar situation; and that, as it carries up the thickness of its huts much higher, they contain Jive or six times the quantity of wood, found in the English species. The Wainscot Oak has hitherto been employed only in making posts, pales, etc; but it appears from Mr. W.'s observations, that it promises to be equally useful as the British trees, for every purpose of ship-building or of carpentry.