No certain specific characters, we are aware, can be derived from the mere size or shape of the acorns, or of the leaves. It may be mentioned, however, as a general, though not a constant rule, that _Quercus sessiliflora_ usually bears very small acorns, and that its leaves are, for the most part, larger, and more regularly laciniated or notched, and consequently handsomer, as _individual leaves_, than those of _Quercus robur_. The foliage of the latter species, however, taken as a whole, is by far the more beautiful; its leaves, being smaller, and growing close to the stem, and not on footstalks, combine better, form more dense and compact masses, and exhibit to greater perfection those exquisite tufts, or rosettes, which constitute one of the peculiar charms of oak foliage. The oak is far less used in civil architecture than formerly, although there are certain purposes in building to which it is still applied; but owing to its value and the demand for it for ships, and to the great labour required to work it, its place is now supplied by _fir_. The best oak is that which grows on cold, stiff, clayey soils, and is the slowest in arriving at maturity; and the colder the climate, or the higher above the level of the sea the tree grows, provided it be not stunted from severity of climate, the better the timber: hence Scottish and Welsh oak is more esteemed than that from the middle or southern counties of Britain. Our own island does not produce this timber in sufficient abundance to supply the demand, and large quantities of oak are imported from different countries, especially from Prussia and Canada. There are four kinds of oak used in the Royal Dock-yards,--Welsh, Sussex, Adriatic, and Baltic,--besides two others, termed African oak, employed in different parts of the vessels, according to the qualities requisite for the particular purpose. Next to our own oak, that from the shores of the Baltic is by far the most esteemed. In domestic architecture, oak is only used in the largest and best buildings, occasionally for the principal beams; but its chief use is for door and window frames, sills, sleepers, king-posts of roofs, for trussing fir girders, for sashes, for gates of locks, sluices, posts, piles, &c. The timber called _African oak_, used in the navy, is wood of a different genus. _Wainscot_ is the wood of a species of oak, imported from Russia and Prussia in a particular form of log.