woo 
vegetables consists of fibres, impregnated 
with a variety of the natural juices of the 
plant, as mucilage, resin, colouring matter, 
extract, essential oil, sugar, &c. 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 longer 
gives out taste or smell, and if it be after- 
wards digested in alcohol, the substance 
which remains is the woody fibre. It is 
either in a fibrous, lamellated, or pulveru- 
lent 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, ex- 
hales dense, acrid, pungent fumes, and leaves 
behind a coaly matter, which does not 
change its form, fiy reducing it to ashes, 
it is found to Contain a little potash, sulphate 
of potash and lime, and phosphate of lime. 
When it is distilled in a tetort it yields wa- 
ter, acetic acid contaminated with oil, a 
thick oily matter, carbonated hydrogen, 
and carbonic acid gases, and a portion of 
ammonia, combined with acetic acid. The 
pure ligneous fibre is decomposed by being 
heated with strong nitric acid, and yields a 
very considerable 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 agreeable ef- 
fect in cabinet work. 
Wood, cutting in, is used for various pur- 
poses; as for initial and figured letters, 
head and tail-pieces of books ; and even for 
schemes, mathematical and other figures, 
to save the expense of engraving on cop- 
per : and for prints, and stamps for papers, 
calicoes, linens, &c. The invention of cutt- 
ing in wood, as well as that in copper, is 
ascribed to a goldsmith of Florence ; but 
Albert Durer and Lucas bfoUght both 
these arts to perfection. About two hun- 
dred years ago, the art of cutting in wood 
was carried to a very great pitch, and 
might , even vie, for beauty and justness, 
with that of engraving on copper : at pre- 
sent it is much neglected, the application of 
artists being wholly employed on copper, 
as the more easy and promising province ; 
not but that wooden cuts have the advan- 
tage of those in copper in many respects; 
chiefly for figures and devices in books ; as 
being printed at the same time and in the 
WOO 
same press With the letters: wherCaS, fof 
the other, there is required a particular and 
separate impression. 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 print- 
ed; or they fasten the design drawn on pa- 
per 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 witli a sponge dipped in wa- 
ter, and then take it off by little and little, 
rubbing it first with the tip of the finger, 
till notliing is left on the block 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 or delicacy of the work. 
Wood pecker. See Picus. 
WOODSTONE, in mineralogy. See 
Hornstone. 
WOODTIN, in mineralogy. See Tin 
ore. 
WOOF, among manufacturers, the threads 
which the weavers shoot across with an in- 
strument called the shuttle. 
WOOL, the covering of sheep. Each 
fleece consists of wool of several qualities 
and degrees of fineness, which the dealers 
therein take care to separate. 
The fineness and plenty of our wool is 
owing, in a great measure, to the short sweet 
grass in many of our pastures and downs ; 
though the advantage of our sheep feeding 
on this grass all the year, without being ob- 
liged to be shut up under cover during the 
winter, or to secure them from wolves at 
other times, contributes not a little to it. 
This substance, the material of such im- 
portant manufactures, possesses some cu- 
lioiis chemical properties, none of which 
however are much illustrated by the va- 
rious operations performed on it in manu- 
facture, almost all (tliat of dying excepted) 
being purely mechanical processes. Some 
of the simple chemical properties of wool 
have been examined by M. Achard, and 
compared with the corresponding proper- 
ties of the hair of different animals. The 
copious generation of oxalic acid by treat- 
ment of Wool with nitric acid, has been 
particularly described and explained by M 
