A C A 
ACC 
ACC 
nually read lectures on the subjects of their 
several departments. 
The Academy of arts at Petersburgh was 
established by the empress Elizabeth. The' 
scholars are admitted at the age of six, and 
continue twelve years; they are lodged, 
clothed, boarded, and taught, at the expence 
of the crown. Besides this, there is the im- 
perial academy of sciences at Petersburgh, 
the transactions of which were formerly en- 
titled Commentarii Academice Scientiurum 
Imperial is Petropolitanx, but now are called 
Nova Acta Acad. Scient. Imp. Petrop. 
Academies of sciences, those chiefly de- 
signed for the improvement of natural his- 
tory and mathematics, with their numerous 
branches, botany, chemistry, mechanics, as- 
tronomy, geography, &c. 
There are many other academies in dif- 
ferent countries : as at Cortuna, for the study 
of Etrurian antiquities ; at Florence and Mi- 
lan, for painting, &c. ; the American, of arts 
and sciences ; the Royal Irish, &c. &c. 
Academy is also more particularly used 
with us for a kind of schools, where youth are 
instructed in various branches of learning. Of 
this kind we have two royal ones, viz. one at 
Portsmouth, for teaching navigation, draw- 
ing, &c. which may be called a naval or ma- 
ritime academy ; and another at Woolwich, 
where youth are taught fortification, gunnery, 
&c. which may be styled the military acade- 
my. Besides these, there are numerous aca- 
demies, especially in London, for teaching 
mathematics, languages, writing, accounts, 
drawing, and other branches of learning. 
The dissenters have likewise their academies 
for teaching philosophy, divinity, &c. See 
University. 
AcADEMY_/?g7£re, in painting, a draught or 
design, made after a model, with a crayon or 
pencil. 
AC.ENA, a genus of the tetandria mo- 
nogvnia class and order of plants. Its essen- 
tial character is, the calyx four-leaved ; co- 
rolla four-petalled ; berry dry, inferior, one- 
seeded, with spines bent backwards. We 
know of only one species, the acsena elonga- 
ta, which is a Mexican shrub of about two 
feet high. 
ACAJOU, the cashew-nut tree. See Ana- 
CARDIUM. 
ACALYPHA, in botany, a genus of the 
monoecia monodelphia class and order. The 
essential character is, in the male blossoms, 
calyx three or four-leaved ; corolla none ; sta- 
mina eight to sixteen. In the female, calyx 
three-leaved ; corolla none ; styles three ; 
capsules three-grained, three-celled ; seed 
one. 
There are fourteen species of this plant : 
some of them annual, and resembling the 
broad leaved pellitory of the wall; some of 
them are shrubs, but none appear to have 
either beauty or utility to recommend their 
cultivation. 
ACANACEOUS plants, those which are 
rickly, and bear their flowers and seeds on a 
ind of heads. 
•ACANGIS, in Turkish military affairs, 
the name of a kind of light-armed horse. 
ACANTHA, the prickles of a thorny 
plant. 
Acantha is also used by zoologists for the 
spines of certain fishes, as those of the echi- 
nus marinus, Ac. 
ACANTHACEOUS, an epithet given to 
all plants of the thistle kind, on account of the 
prickles with which they are beset. 
ACANTHOPTERYGIOUS fishes, one 
of the general classes or families of fishes ; 
distinguished by having the rays of their fins 
bony, and some of them prickly at the ex- 
tremities. 
ACANTHUS, bear’s breech, in botany, a 
genus of plants of the class and order didyna- 
mia angiospermia. The essential character 
is, calyx two-leaved, bifid ; corolla one-lipp- 
ed, bent down, trilid ; capsules two-celled. 
See Plate Nat. Hist. fig. 1. 
There are about ten species, only four of 
which are exotic and tender. The acanthus 
mollis, or smooth-leaved acanthus, is that 
which was formerly used in medicine, though, 
we apprehend, with little effect, as it seems 
to differ very little in its medical virtue from 
the altheas, and other mucilaginous vegeta- 
bles. It is also the plant which is said to have 
afforded the hint to Callimachus for the in- 
vention of the Corinthian capital. The Go- 
thic sculptors are supposed to have adopted 
for their ornament the leaves of the acanthus 
spinosus. 
AC ARU S, the tick or mite, a numerous 
genus of insects, of the order of aptera, or 
those which have no wings. The acarus has 
eight legs ; two eyes, one on each side of the 
head ; and two jointed tentacula. They are 
in general very prolific. The eggs of the 
cheese mite hatch in about fourteen days in 
summer, but in winter take more. Ninety 
millions of these eggs may be comprehended 
in the size of a pigeon’s. The acarus will live 
seven months without food. There are thirty- 
five species. See Plate Nat. Hist. fig. 1-— 
3. 
ACATALECTIC, a term in antient poe- 
try, apslicable to such verses as have all their 
feet and syllables, without any defect at the 
end. In the following lines of Horace, the 
first two are acatalectic, the last catalectic : 
Solvitur acris, hyems, grata vice 
Veris et Favoni ; 
Trahuntque siccas machine Carinas, 
ACATALEPSY, among antient philoso- 
phers, the impossibility of comprehending 
something. The distinguishing tenet of the 
pyrrhonists was, their asserting an absolute 
acatalepsy with regard to every thing. 
ACAl'ERY, or Accatry, an officer of 
the king’s household, designed to be a check 
between the clerks of the kitchen and the 
purveyors. 
ACATIUM, in antiquity, a kind of boat 
or pinnace used in military affairs. The aca- 
tium was a species of the naves actuaries. 
ACAULOSE, or Acaulous (Acaulis), 
among botanists, a term used for such plants 
as have no caulis, or stem. 
AC CALI A, in Roman antiquity, solemn 
festivals held in honour of Acca Laurentia, 
Romulus’s nurse : they were otherwise called 
Laurentalia. 
ACCAPITARE, in our old law books, the 
act of becoming a vassal, or paying homage 
to some lord. Hence 
ACCAP1TUM, signified the money paid 
by a- vassal upon such an occasion. 
It is likewise used for the relief due to the 
chief lord. See Relief. 
ACCEDAS ad curiam, inlaw, a writ lying 
where a man has received or fears false judg- 
ment in a hundred-court, or court-baron. It 
7 
is issued out of the Chancery, and directed to 
the sheriff; but returnable in the King’s 
Bench or Common Pleas. It lies also for jus- 
tice delayed, and is said to be a species of the 
writ Recordare. 
ACCELERATION, in mechanics, de- 
notes the augmentation or increase of motion 
in accelerated bodies. The accelerated mo- 
tion of falling bodies is produced by the im- 
pulse of gravity, which keeps continually act- 
ing upon them, and thereby communicates a 
new augmentation of motion every instant. 
If this increase is equal in equal times, the 
motion is said to be uniformly accelerated. 
See Mechanics. 
Acceleration, in astronomy, is a term 
applied to the fixed stars. The diurnal ac- 
celeration is the time by which the stars, in 
one diurnal revolution, anticipate the mean 
diurnal revolution of the sun; that is, a star 
rises or sets, or passes the meridian, about 
3' 36" sooner each day. This apparent ac- 
celeration of the stars is ow'ing to the real re- 
tardation of the sun, which depends upon his 
apparent motion towards the east, and that is 
at the rate of 59' 8-1" daily : therefore to find 
the acceleration we say. As 360°: 59' 8^": : 
24h. : 3 min. 56 sec. nearly, the acceleration 
required. 
This acceleration serves to regulate the 
length and vibrations of pendulums. If, fot 
instance, the pendulum marks 9h. 6m. when 
a fixed star sets or passes behind any object 
one day ; and on the next, the eye being pre- 
cisely in the same situation, the same appear- 
ance occurs at 9h. 2m. 4s. by the pendulum ; 
it may be inferred, that such a pendulum is 
truly regulated, or measures time accurately. 
Acceleration of the moon, is a term 
used to express the increase of the moon’s 
mean motion from the sun, compared witk 
the diurnal motion of the earth, which is said 
to be about 1 0" in a hundred years. This by 
some is thought to be occasioned by the sun 
becoming less from the particles of light con- 
tinually flowing from it, v r hich renders the 
motion of the earth slower ; or if the earth’s 
by any means be increased, the motion of the 
moon will be accelerated. This acceleration 
is shewn by M. La Place to arise from the 
action of the sun upon the moon, combined 
with the variation of the eccentricity of the 
earth’s orbit. 
ACCENDENTES, or Accensores, in 
the church of Rome, a lower rank of minis- 
ters, whose business it is to light, snuff, and 
trim the candles and tapers. 
ACCENDONES, or Accedones, in 
Roman antiquity, a kind of officers in the 
gladiatorian schools, who excited and animat- 
ed the combatants during the fight. 
ACCENSI, in the Roman armies, certain 
supernumerary soldiers, designed to supply 
the place of those who should be killed, or 
anywise disabled. Accensi also denoted a 
kind of inferior officers, appointed to attend 
the Roman magistrates, 
ACCENT, in a general sense, denotes a 
certain tone or manner of speaking peculiar to 
some nation, country, or province ; thus we 
say, the Scotch accent, the Irish accent, &c. 
Among grammarians, it is the raising or low- 
ering the voice in pronouncing certain syl- 
lables. 
We hay# three kinds of accents, viz. the 
acute, the grave, and the circumflex. The 
acute accent, marked thus ('), shews that the 
