Encyclopaedia Britannica > Volume 7, ETM-GOA

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Evo:ati tLemfclves eunuchs for the kingdom of heaven,” ca-
,, II . ftrated hitnfelf.
vo vu,us.^ EVOCATIj foldiers among the Romans, who ha¬
ving ferved their full time in the army, went after-
w'ards volunteers at the requelt of fome fiivourite gene¬
ral ; on which account they were called by the honour¬
able names of Emeriti and Benejiciarii.
EVOCATION (Eyocaiio,) among the Romans, a
religious ceremony always obferved by them at the un¬
dertaking a liege, wherein they folemnly called upon
the gods and goddefl'es of the place to forfake it and
come over to them. Without the performance of this
ceremony, they either thought that the place could
not be taken, or that it would be a facrilege to take
the gods prifoners. They always took it for granted
that their prayer was heard, and that the gods had de-
ferted the place and come over to them, provided they
were able to make themfelves mailers of it.
EUODIA, in botany r A genus of the monogynia
order, belonging to the tetrandria clafs of plants. The
calyx is a tetraphyllous perianthium; the corolla con fids
of four fpathulated, lharp, and open petals; the ftatni-
na are four fubulated filaments as long as the petals;
the pericarpium four, roundilh, bivalve, and mono-
fpermous capfules ; the feeds folitary.
EVOLUTION, in algebra, the unfolding or open¬
ing of a curve, and making it defcribe an evolvent.
The word evolutio is formed of the prepofition e “ out;”
and volvo “ I roll, or wind ;” q. d. an unwinding, or
unrolling.
The equable evolution of the periphery of a circle,
or other curve, is fuch a grad ual approach of the cir¬
cumference to re&itude, as that its parts do all concur
and equally evolve or unbend; fo that the fame line
becomes fuccefiively a lefs arc of a reciprocally greater
, circle ; till at laft they change into a ftraight line. In the
Philofophical Tranfadtions, N° 260. a new quadratrix
to the circle is found by this means, being the curve
. defcribed by the equable evolution of its periphery. ^
Evolution, is alfo ufed for the extradlion of roots
out of powers; in which fenfe it Hands oppofed to in¬
volution. See Algebra, p. 413.
Evolution, in the art of war, the motion made by
a body of troops, when they are obliged to change
their form and difpofition, in order to preferve a poll
or occupy another, to attack an enemy with more ad¬
vantage, or to be in a condition of defending them¬
felves the better.
It con fills in doublings, counter-marches, conver-
fions, See. A battalion doubles the ranks, when attack¬
ed in front or rear, to prevent its being flanked or fur-
rounded ; for then a battalion fights with a larger front.
The files are doubled, either to accommodate themfelves
to the neceffity of a narrow ground, or to refill an ene-
memy that attacks them in flank. But if the ground
will allow it, converfion is much, preferable ; becaufe,
after converfion, the battalion is in its firft form, and
oppofes the file-leaders, which are generally the bell
men, to the enemy ; and likewife, becaufe doubling
the files in a new or not well difciplined regiment, they
may happen to falf intodiforder. See Doubling.
EVOLVULUS, in botany : A genus of the tetra-
gynia order, belonging to the pentandria clafs of plants;
and in the natural method ranking under the 29th or-
6 ] E U P
der, Campanacea. The calyx is pentaphyllous; the co- Eucnymus-
rolla quinquefid and verticillated; the capfule trilocular;
the feeds folitary. Eupatrulx.
EUONYMUS, the spindle-tree: A genus of v "
the monogynia order, belonging to the pentandria clafs
of plants ; and in the natural method ranking under the
43d order, Dumofa. The corolla is pentapetalous; the
capfule pentagonal, quinquelocular, quinquevalved, and-
coloured ; the feeds hooded. There are two fpecies,
1. The europaDus, hath an upright woody item i o or
15 feet high, garniflied with oblong oppofite leaves :
from the lides of the branches proceed finall bunches of
greenifh quadrifid flowers, fucceeded by pentagonous
capfules, difclofing their feeds in a beautiful manner in
autumn. 2. The americanus, or evergreen fptndle-
tree, hath a flmibby ftem, dividing into many oppofite:
branches, rifing fix or eight feet high, garnilhed with
fpear- lhaped evergreen leaves growing oppofite, and from
the fides and ends of the branches. The flowers are
quinquefid and whitilh, and come out in fmall bunches,
fucceeded by roundilh, rough, and protuberant cap¬
fules, which rarely perfect their feeds in this country.
Both thefe fpecies are hardy, and will fucceed in any
foil or fituation. The berries of the firil fort vomit and
purge very violently, and are fatal, to Iheep. If pow¬
dered and fprinkled upon hair, they deftroy lice. If
the wood is cut when the plant is in blofibm, it is tough
and not eafily broken ; and in that ftate it is ufed by
watchmakers for cleaning watches, and for making
Ikewers and tooth-pickers. Cows, goats, and Iheep, eat
this plant; horfes refufe it.
EUPATORIUM, hemp-agrimony : A genus of
the polygamia aequalis order, belonging to the fynge-
nefia clafs of plants; and in the natural method ranking
under the 49th order, Compofita. The receptacle is
naked ; the pappus feathery ; the calyx imbricated and
oblong; the flyle femibifid and long. There are 13
fpecies, many of them herbaceous flowery perennials,
producing annual italks from two to three or five feet
high, terminated by clufters of compound flowers of a
red, purple, or white, colour. They are eafily propa¬
gated by feeds, or parting the roots in autumn of
fpring. One fpecies, viz. the cannabinum, or water
hemp-agrimony, is a native of Britain. It is found
wild by the fides of rivers and ditches, and has pale-
red bloflbms. It has an acrid fmell, and a very bitter
tafte, with a confiderable fhare of pungency. The
leaves are much recommended for ftrengthening the tone
of the vifeera, and as an aperient; and faid to have ex¬
cellent effects in the dropfy, jaundice, cachexies, and
fcorbutic diforders. Boerhaave informs us, that this is
the common medicine of the turf-diggers in Holland,
againfl feurvies, foul ulcers, and fwellings in the feet)
to which they are fubjea. The root of this plant is
faid to operate as a ftrong cathartic: but it is hardly
ufed in Britain, and has no place in our pharmacopceias.
EUPATRIDiE, in antiquity, a name given by
Thefeus to the nobility of Athens, as diftinguiflied from
the Geomori and Demiurgi. The Eupatridse, by The-
feus’s eftablifliment, had the right of choofing magi-
flrates, teaching and difpenfing the laws, and interpre¬
ting holy and religious myfteries. The whole city, in
all other matters, was reduced to an equality. The
Geomori were hufbandmen, and inferior to the Eiipa-
tridss.