VEG 
elevation, and are besides more firm and 
durable. 
VECTOR, or Radius Vector, in astro- 
nomy, is a line supposed to be drawn from 
any planet moving round a centre, or the 
focus of an ellipse, to that centre, or focus. 
It is so called, because it is that line by 
which the planet seems to be carried round 
its centre; and with which it describes 
areas proportional to the times. 
VEER, a sea term variously used. Thus 
veering out a rope, denotes the letting it go 
by hand, or letting it run out of it|elf. It 
is not used for letting out any running rope 
except the sheet. 
VEGETABLE. See Botany, Plant, 
&c. A vegetable is composed of a root, 
stem, leaves, flowers, fruits, and seeds; and 
when all these different parts are fully deve- 
loped, the vegetable is said to be perfect. 
When any are deficient, or at least less ob- 
vious, the vegetable is said to be imperfect. 
The root is that part of the plant which is 
concealed in the earth, and which serves to 
convey nourishment to the whole plant. 
The stem, which commences at the termi- 
nation of the root, supports all the other 
parts of the plant. AVhen the stem is large 
and solid, as in trees, it is denominated the 
trunk, which is divided into the wood and 
the bark. The bark constitutes the outer- 
most part of the tree, and covers the whole 
of the plant from the extremity of the 
roots to the termination of the branches. 
The bark is composed of three parts, 
namely the epidermis, the parenchyma, and 
cortical layers. The epidermis, which is a 
thin transparent membrane, forming the ex- 
ternal covering of the bark, is composed of 
fibres crossing each other. When the epi- 
dermis is removed, it is reproduced. The 
parenchyma, which is immediately below 
the epidermis, is of a dark-green colour, 
composed of fibres crossing each other in 
all directions, and is succulent and tender. 
The cortical layers which constitute the 
interior part of the bark, are composed of 
thin membranes, and increase in number 
with the age of the plant. The wood 
immediately under the bark, is composed 
of concentric layers,- which Increase witli 
the age of the plant, and may be separated 
into thinner layers which are composed of 
longitudinal fibres. The wood next the 
bark, which is softer and whiter, is called 
the alburnum. The interior part of the 
trunk is browner and harder, and is deno- 
minated the perfect wood. 
In the middle of the stem is the pith, 
VEG 
which is a soft, spongy substance, com- 
posed of cells. In old wood this part en- 
tirely disappears, and its place is occupied 
by the perfect wood. 
The leaves are composed of fibres ar- 
ranged in the form of net-wOrk, which pro- 
ceed from the stem, and footstalk, by which 
they are attached to the branches. Tliese 
fibres form two layers in each leaf, which 
are destined to perform different functions. 
The leaves are covered with the epidermis, 
which is common to the whole of the plant. 
Each surface of a leaf has a great number 
of pores and glands, which absorb or emit 
elastic fluids. 
Flowers are composed of different parts. 
The calyx or cup is formed by the exten- 
sion of the epidermis ; the corolla is a con- 
tinuation of the bark, and the stamina and 
pistilla, the internal parts of fructification, 
are composed of the woody fibres and pith 
of the plant. Fruits are usually composed 
of a pulpy, parenchymatous substance, 
containing a great number of vesicles, and 
traversed by numerous vessels. Seeds are 
constituted of the same utricular texture, 
in the vesicles of which is deposited a pul- 
verulent or mucous substance. These cells 
have a communication with the plants by 
means of vessels, and by these is conveyed 
the necessary nourishment during germina. 
tion. 
Plants contain difterent orders of vessels, 
which are distinguished from each other by 
their course, situation, and uses. Lympha- 
tic vessels serve for the circulation of the 
sap. They are chiefly situated in the 
woody part of the plant. The peculiar 
vessels, which generally contain thick or 
coloured fluids, are placed immediately un- 
der the bark ; they are smaller in number 
than the sap vessels, and have thin inter- 
stices filled up with utriculi or cells, with 
which they form a communication. Some 
of these proper vessels are situated be- 
tween the epidermis and the bark, which 
are readily detected in the spring. Some 
are situated in the interior part of the bark, 
forming oval rings, and filled with the pecu- 
liar juices of the plant. Another set of 
proper vessels is placed in the alburnum, 
nearer the centre of the stock or trunk, 
and sometimes in the perfect wood. The 
utriculi or cells constitute another set of 
vessels, which seem to resemble a flexible 
tube, slightly interrupted with ligatures at 
pearly equal distances, but still preserving 
a free communication through its whole 
length. They vary in form, colour, and 
