prize of the other. The United States had too weak a fleet to declare war, and, therefore, tried to bring the two powers to terms by preventing her own vessels from trade. The southern party, chiefly agricultural, was in power, and their action crippled New England, which was so hard hit by its loss of trade that it threatened to secede. A stricter embargo-act was passed in 1807. Exports fell from $110,084,207 in 1807 to $22,430,960 in 1808. The American carrying-trade has never since fully recovered. England, the chief offender in seizing American ships and pressing American sailors (for France did not command the sea), alone profited by the American embargoes. In 1809 the embargo was removed, but in its stead a non-intercourse act was passed against trade with France or England. War broke out with England in 1812. A new embargo was levied until 1814. In spite of the opinion of Jefferson, it seems clear that the embargoes injured the home country more than her enemies, and thus were unsound.
Em′bryo (in plants), a plant in the earliest
stages of its development. In Spermatophytes
Embryo of capsella, showing superior (below) and embryo (above) in various stages of development.
the name
is restricted to
the development
within the seed.
Taking the bean
embryo as an
illustration, it
consists of a
small stem, once
called the caulicle,
but now
known as the
hypocotyl, from
the lower end of
which the root
develops, and at
the upper end
two large and fleshy leaves appear (the halves
of the bean), called the cotyledons.
Between the cotyledons a little bud is
apparent, called the plumule, in which
the subsequent leaves are more or less
formed, and which is to develop into
the shoot when the embryo escapes from
the seed. Such an embryo represents the
common form among the dicotyledons.
Among the monocotyledons, as in corn, the
same parts appear, but the single large
cotyledon is terminal on the hypocotyl, and the
stem tip comes out at one side. Among the
conifers, as in pines, a rosette of cotyledons
may appear, in the center of which is the
plumule. In the development of the
embryos of seed-plants a temporary organ,
called the suspensor, usually appears. It
generally is a more or less elongated
filament of cells, which at its tip
bears the cell which is to form the
real embryo, and by its growth places
this cell in a better position in reference
to the food-supply which is forming in
the seed.
Embryology. See Development.
Em′bryo-Sac (in plants). In the ovule of
angiosperms there is developed what appears
to be a large cavity, but is really a single
large spore which is not discharged (see
Megaspore). This spore germinates and
develops within itself a very simple gametophyte
consisting of seven cells (see
Gametophyte). This spore containing its gametophyte,
before it was known to be a spore,
SECTION OF OVULE
was called the embryo-sac,
because the
embryo was observed to
develop within it. At
one end of the sac
three of the seven cells
are grouped together,
the group being called
the egg-apparatus,
since the central cell is
the egg, which is to
produce the embryo,
and the other two aid
it in the process of
fertilization. At the
opposite end of the sac
is another group of
three cells known as
the antipodal cells.
Usually they disappear very soon after they
are formed. In the central region of the
sac a very large cell appears, called the
definitive nucleus or endosperm nucleus. It
is this cell which produces the endosperm or
food-cells for the use of the embryo. In
many seeds, as corn and wheat, it is the
endosperm which supplies the food-material
used by man.
Emerald, a mineral differing in nothing but color from beryl. The emerald is highly esteemed as a gem. It owes its value mainly to its very beautiful velvety-green color. It is found in very few places. The finest have long been brought from Colombia, where they are got from veins in slate and granite. Valuable stones also come from the upper Orinoco in Venezuela. Poor stones are found in Europe, in Salzburg and the Ural Mountains, and some old mines in Egypt yield them. The gem was known and highly prized in early times. Ptolemy offered a famous poet, who visited his court, an emerald set in gold, with his portrait engraved on it. Nero, who was near-sighted, looked at the combats of gladiators through an eyeglass of emerald. An emerald is rarely without a flaw, and its value depends on its color. A very perfect emerald of six carats has been sold for $5,000. The name of oriental emerald is often given to a very rare, beautiful and precious green sapphire.
Emer′gence (in plants), outgrowths from the surface of a plant, such as warts, prickles, etc., which involve in their origin
