WOOD, (Encycl.) The art of moulding wood is mentioned by Mr Boyle as a desideratum in the art of carving. He says, he had been credibly informed of its having been practised at the Hague; and suspects that it might have been performed by some menstruum that softens the wood, and afterwards allows it to harden again, in the manner that tortoise-shell is moulded; or, perhaps, by reducing the wood into a powder, and then uniting it into a mass with strong but thin glue. And he adds, that having mixed saw-dust with a fine glue made of isinglass, slightly straining out
what was superfluous through a piece of linen, the remainder, formed into a ball and dried, became so hard as to rebound when thrown against the floor.
The people who work much in wood, and that about small works, find a very surprising difference in it, according to the different seasons at which the tree was cut down; and that not regularly the same in regard to all species, but different in regard to each. The button-mould makers find that the wood of the pear-tree cut in summer works toughest; holly, on the contrary, works toughest when cut in winter; box is mellowest when in it has been cut in summer, but hardest when cut about Easter; hawthorn works mellow when cut about October; and the service is always tough if cut in summer.
Woods are distinguished into divers kinds, with regard to their nature, properties, virtues, and uses. Of wood, considered according to its qualities, whether useful, curious, medicinal, &c. the principal is called timber, used in building houses, laying floors, roofs, machines, &c.
Woods valued on account of their curiosity, are cedar, ebony, box, calambo, &c. which by reason of their extraordinary hardness, agreeable smell, or beautiful polish, are made into tables, combs, beads, &c.
The medicinal woods are guaiacum, aloes, sassafras, nephriticum, santal, farapaparilla, aspalanthum, &c.
Woods used in dyeing are brazil-wood, Campechy-wood, &c.
Fossil Wood. Fossil wood, or whole trees, or parts of them, are very frequently found buried in the earth, and that in different strata; sometimes in stone, but more usually in earth; and sometimes in small pieces loose among gravel. These, according to the time they have lain in the earth, or the matter they have lain among and in the way of, are found differently altered from their original state; some of them having suffered very little change; and others being so highly impregnated with crystalline, sparry, pyritical, or other extraneous matter, as to appear mere masses of stone, or lumps of the common matter of the pyrites, &c. of the dimensions, and, more or less, of the internal figure of the vegetable bodies into the pores of which they have made their way.
The fossil wood which we find at this day, are, according to these differences, arranged by Dr Hill into three kinds; 1. The less altered; 2. The pyritical; and, 3. The petrified.
Of the trees, or parts of them, less altered from their original state, the greatest store is found in digging to small depths in bogs, and among what is called peat or turf earth, a substance used in many parts of the kingdom for fuel. In digging among this, usually very near the surface, they find immense quantities of vegetable matter buried, and that of various kinds: in some places there are whole trees scarce altered, except in colour; the oaks in particular being usually turned to a jetty black; the pines and firs, which are also very frequent, are less altered, and are as inflammable as ever, and often contain between the bark and wood a black resin. Large parts of trees have also been not unfrequently met with unaltered in beds of another kind, and at much greater depths, as in the strata of clay and loam, among gravel, and sometimes even in solid stone.
Beside these harder parts of trees, there are frequently found also in the peat-earth vast quantities of the leaves and fruit and catkins of the hazel and the like trees: these are usually intermixed among the sedge and roots of grass, and are scarce at all altered from their usual texture. The most common of these are hazel nuts; but there are frequently found also the twigs and leaves of the white poplar; and a little deeper usually there lies a cracked and shattered wood, the crevices of which are full of a bituminous black matter; and among this the stones of plums and other stone-fruits are sometimes found, but that more rarely.
It is idle to imagine, that these have been thus buried either at the creation, or, as many are fond of believing, at the universal deluge. At the first of these times the strata must have been formed before the trees were yet in being; and the peat-wood is so far from being of antediluvian date, that much of it is well known to have been growing within these 300 years in the very places where it is now found buried.
In this state that is little altered from their original condition, it is that the fruits and larger parts of trees are usually found: what we find of them more altered, are sometimes large and long, sometimes smaller and shorter branches of trees, sometimes small fragments of branches, and more frequently small shapeless pieces of wood. The larger and longer branches are usually found bedded in the strata of stone, and are more or less altered into the nature of the stratum they lie in. The shorter and smaller branches are found in vast variety in the strata of blue clay used for making tiles in the neighbourhood of London. These are prodigiously plentiful in all the clay-pits of this kind, and usually carry the whole external resemblance of what they once were, but nothing of the inner structure; their pores being wholly filled, and undistinguishably closed, by the matter of the common vitriolic pyrites, so as to appear mere simple masses of that matter. These fall to pieces on being long exposed to moisture; and are so pregnant in vitriol that they are what is principally used for making the green vitriol or copras at Deptford and other places.
The irregular masses or fragments of wood are prin-
cipally of oak, and are most usually found among gravel; though sometimes in other strata. These are variously altered by the infestation of crystalline and stony particles; and make a very beautiful figure when cut and polished, as they usually keep the regular grain of the wood, and show exactly the several circles which mark the different years growth. These, according to the different matter which has filled their pores, assume various colours, and the appearance of the various fossils that have impregnated them; some are perfectly white, and but moderately hard; others of a brownish black, or perfectly black, and much harder; others of a reddish black, others yellowish, and others greyish, and some of a ferruginous colour. They are of different weights also and hardnesses, according to the nature and quantity of the stony particles they contain: of these some pieces have been found with every pore filled with pure pellucid crystal; and others in large masses, part of which is wholly petrified and seems mere stone, while the rest is crumbly and is unaltered wood. That this alteration is made in wood, even at this time, is also abundantly proved by the instances of wood being put into the hollows of mines, as props and supports to the roofs, which is found after a number of years as truly petrified as that which is dug up from the natural strata of the earth. In the pieces of petrified wood found in Germany, there are frequently veins of spar or of pure crystal, sometimes of earthy substances, and often of the matter of the common pebbles: these fragments of wood sometimes have the appearance of parts of the branches of trees in their natural state, but more frequently they resemble pieces of broken boards; these are usually capable of a high and elegant polish.
Many substances, it is certain, have been preserved in the cabinets of collectors, under the title of petrified wood, which have very little right to that name. But where the whole outer figure of the wood, the exact lineaments of the bark, or the fibrous and siliular texture of the striæ, and the vestiges of the utriculi and tracheæ or air-vessels, are yet remaining, and the several circles yet visible which denoted the several years growth of the tree, none can deny these substances to be real fossil wood.