"Sandal-wood is the produce of a species of Sandoricum belonging to the family Meliaceæ; the wood is of a light brown colour with golden-coloured waves. "Ebony and Iron-wood are the names given to some very hard woods, the produce of the natural order Ebenaceæ. These woods are mostly brought from India, although some of the species are found in Europe and America. "There are several other woods occasionally used amongst cabinet-makers, of which little is known, either with regard to the places they come from, or the trees to which they belong. Canary-wood has a yellow colour; Purple-wood has a purple colour, without veins; Snake-wood is of a deep colour with black shades; Calander-wood is a handsome cheap wood taking a high polish, and is brought from Ceylon. "Other woods are named after the places they come from, as Coromandel-wood, Amboyna-wood, &c." Woods are largely used as dye-stuffs; the chief of these is log-wood, which has a deep red colour, is very heavy and solid, and yields a great deal of red colouring matter. It is very astringent, and contains tannic and gallic acids, from which properties it produces a deep black colour when mixed with any of the salts of iron; from this peculiarity it is very valuable as a black dye, but the black dye so extensively used for dyeing cloth, is, for the most part, made from galls, or "nut-galls," as they are sometimes called. These are hard round substances found growing on many species of oak, chiefly the "Quercus infectoria," and the best are brought from Aleppo; they are diseased growths produced by a little insect, called the "Cynips Quercus," which deposits its eggs under the epidermis of the leaf, and the juice collects and forms the gall (fig. 22), from the interior of which the larva eats its way out; thus it will be found that every gall must have a little round hole in it, whence the larva of the cynips has issued. [Illustration: FIG. 22--ALEPPO GALL.] The root of the Madder plant (Rubia tinctorum) produces the most beautiful and permanent of our red dyes, and the cochineal insect (Coccus cacti) obtains its colour from feeding upon the cactus. A useful and very permanent blue dye is obtained from Indigo, a kind of extract from the plant "Indigofera," growing in India and other places, and many other members of the vegetable kingdom yield dyes and colours used in the arts. Amongst the various and almost endless purposes to which wood is applied, that of serving as a material to engrave on and print from must not be omitted. The wood used for this purpose is that of the box-tree (Buxus sempervirens), which furnishes a close, even-grained, hard wood, admirably suited to the purpose; and the cultivation and perfecting of this most admirable art, has produced an improvement in book-illustrating which can hardly be sufficiently appreciated.