WOOD. See Tx st HER. The wood o vegetables consists of fibres, impregnated with a variety of the natural juices of the plant, as mucilage, resin, colouring mat ter, extract, essential oil, sugar, 8,cc. All of these may be obtained from one or other kind of wood, by applying those menstrua which dissolve these substances in their natural state. If a piece of wood be boiled in a great quantity of water, till it no lon ger gives out taste or smell, and if it be afterwards digested in alcohol, the sub stance which remains is the woody fibre. It is either in a fibrous, lainellated, or pnlverulent form. This substance, which is more or less coloured, has neither taste nor smell ; is not altered by exposure to the air ; and is insoluble in water and alcohol. When it is heated in contact with air, it blackens, exhales dense, acrid pungent fumes, and leaves behind a coaly matter, which dues not change its form. By reduc ing it to ashes, it is found to contain a little potash, sulphate of potash and lime, and of phosphate of lime. When it is distilled in a retort it yields water, acetic acid con taminated with oil, a thick oily matter, carbonated hydrogen, and carbonic acid gases, and a portion of ammonia, combin ed with acetic acid. The pure ligneous fibre is decomposed by being heated with strong nitric acid, and yields a very con siderable quantity of oxalic and malic acid. The surface of wood is readily stained by a variety of substances; and if these are allowed to remain in contact with it, they sink into the substance of the wood, which often produces a very agree able effect in cabinet work.
Woon, cutting in, is used for various purposes ; as for initial and figured letters, head and tail pieces of books ; and even for schemes, mathematical and other fig ures, to save the expense of engraving on copper : and for prints and stamps for pa pers, calicoes, linens, &c. The invention
of cutting in wood, as well as that in cop per, is ascribed to a goldsmith of Flo rence : but Albert Durer and Lucas brought both these arts to perfection. About two hundred years ago, the art of cutting in wood was carried a very great pitch, and might even vie, for beauty and justness, with that of engraving on copper : at present it is much neglected, the application of artists being wholly em ployed on copper, as the more easy and promising province : not but that wooden cuts have the advantage of those in cop per in many respects ; chiefly for figures and devices in books; as being printed at the same time, and in the same press with the letters : whereas, for the other, there is required a particular and separate im pression. The cutters in wood begin with preparing a plank or block of the size and thickness required, and very even and smooth on the side to be cut : for this they usually take pear tree, or box ; but the latter is best, as being closest, and least liable to be worm eaten. On this block they draw their design with a pen or pencil, exactly as they would have it printed ; or they fasten the design drawn on paper upon the block with paste and a little vinegar, the strokes or lines turned towards the wood. When the paper is dry, they wash it gently with a sponge dipped in water, and then take it off by little and little, rubbing it first with the tip of the finger, till nothing is left on the black but the strokes of ink that form the design, which mark out what part of the block is to be spared or left standing, The rest they cut off very carefully with the points of very sharp knives, chissels, or gravers, according to the bigness cc delicacy of the work.