#60 C I 11 
language. Intoxicated with a barbarous 
zeaJ, they renounced agriculture, professed 
continence, and assumed the title ot “ vindi- 
cators qf justice, and protectors of the op- 
pressed. ’ 1 o accomplish their mission, they 
enlranchised slaves, scoured the roads; forced 
masters to alight troin their chariots, and run 
before tneir slaves, whom they obliged to 
mount in their place; and discharged debt- 
ors, killing tiie creditors if they refused to 
cancel tire bonds. The counts Ursacius and 
Taurinus were employed to quell them: they 
destroyed a great number of them, of whom 
the donatists made as many martyrs. Ursa- 
cius, who was a good catholic, and a religious 
man. having lost his life in an engagement 
x\ith tire barbarians, the donatists did not tail 
to triumph in his death, as an effect of the 
vengeance oi heaven. Africa was the theatre 
ot these blood) scenes during a great part of 
Constantine’s life. 
C.IRCU IT, or Circuity, in law, signifies 
a longer course of proceedings than is need- 
ful to recover the thing sued for: in case a 
person grants a rent-charge of 10/. a year 
ot his manor, and afterwards the grantee dis- 
seises the grantor, who thereupon brings an 
assise, and recovers the land, and 20/. da- 
mages ; which being paid, the grantee brings 
hts action for 10/. ot the rent, due during 
the time of his disseisin. This is termed cir- 
cuity of action, because as the grantor w as to 
receive 20/. damages, and pay 10/. rent, he 
might only have received 10/. for the da- 
mages, and the grantee might have retained 
the other 10/. for his rent, and by that means 
saved his action. 
Circuit also signifies the journey or pro- 
gress which the judges take twice every year 
through the several counties of England and 
Males, to hold courts and administer justice, 
where recourse cannot be had to the king’s 
courts at Westminster. Hence England is 
xlivided into six circuits, viz. the home cir- 
cuit, Norfolk circuit, midland circuit, Oxford 
circuit, western circuit, and northern circuit. 
In Wales there are but two circuits, north 
and south Whiles : two judges are assigned 
by the king’s commission to every circuit. 
In Scotland there are three circuits, viz. the 
southern, w estern, and northern, which are 
likewise made twice every year, viz. in spring 
and autumn. 
C IRCULAR sailing, is the method of 
sailing by the arch of a great circle. See 
Navigation. 
Circular •velocity, in astronomy, signifies 
the velocity of any planet or revolving bodv, 
which is measured by the arch of a circle. ’ 
CIRCULATION of the blood. See Phy- 
siology. 
CIRCUMFERENCE, the curve line 
w hich bounds a circle ; and otherwise called 
♦i periphery, the boundary of a right-lined 
figure being expressed by the term perimeter. 
Any part of the circumference is called an 
arch, and a right line drawn from one ex- 
treme ofthe arch to the other is called a 
chord. The circumference of everv circle 
is supposed to ,be divided into 360 degrees. 
The angle at the circumference of a circle is 
doubled hat at the centre. 
(. IRC i Mi: t.ii LN | OR, an instrument 
ir-ed by surveyors for taking ancles. See 
Surveying. 
C1.RCT MSCRTBED, in geometry, is said 
of a figure which is drawn round another 
Cl R 
figure, so that ail its sides or planes touch the 
inscribed figure. 
Circumscribed hyperbola, one of sir 
Isaac Newton’s hyperbolas of the second or- 
der, that cuts its asymptotes, and contains 
the parts cut off within its own space. 
CIRCUMSCRIBING, in geometry, de- 
notes the describing a polygonous figure 
about a circle, in such a manner that all its 
sides shall be tangents to the circumference. 
Sometimes the term is used for the describ- 
ing a circle about a polygon, so that each 
side is a chord ; but in this case it is more 
usual to say the polygon is inscribed, than 
the circle is circumscribed. 
CIRCUMS i ANTIBUS, in law, a term 
used lor supplying and making up the number 
of jurors (m case any impannelled appear 
not ; or appearing, are challenged by either 
party), by adding to them so many of the 
persons present as will make up the number, 
in case they are properly qualified. 
C1RCUMY ALLATION, or line of cir- 
cumvallation, in military affaire, implies a 
fortification of earth, consisting of a parapet 
and trench, made round the town intended 
to he besieged, when any molestation is ap- 
prehended from parties ofthe enemy, which 
may march to relieve the place. Care is to 
be taken to have the most exact plan of it 
possible; and upon this the line of circumval- 
lation and the attack are projected. This 
line, being a fortification opposed to an ene- 
my that may come from the open country to 
relieve (lie besieged, ought to have its' de- 
fences directed against them ; that is, so as to 
fire from the town; and the besiegers are to 
be encamped behind this line, and between 
it and the place. The camp should be as 
much as possible out of the reach of the 
shot of the place; and the line of cireumvalla- 
tion, which is to he farther distant from the 
place than the camp, ought still more to be 
out of the reach of its artillery. 
As cannon are never to be fired from the 
rear of the camp, this line should be upwards 
of 1200 fathoms from the place; we will sup- 
pose its distance fixed at 1400 fathoms from 
the covert-way. The depth of the camp 
may be computed at about 30 fathom ; and 
from the head of the camp to the line of cir- 
cumvallation 120 fathoms, that the army may 
have room to draw up in order of battle at 
the head ofthe camp, behind the line. This 
distance added to the 30 fathoms makes 150 
fathoms, which being added to the 1400, 
makes 1550 fathoms to constitute the distance 
ot the line of circumvallation from the covert- 
way. The top of this line is generaliv 12 
feet broad, and seven feet deep. The' pa- 
rapet runs quite round the top of it, and at 
certain distances is frequently strengthened 
with redoubts and small fort's: the base IB 
feet wide, the height within six, and on the 
outside five feet, with a banquette of three 
feet wide and one and a half high. 
CIRCUS, in antiquity, a great building of 
a round or oval figure,’ erected by the un- 
dents, to exhibit shows to the people. The 
Roman circus was a large oblong edifice, 
arched at one end, encompassed with porti- 
coes, and furnished with two rows of seats 
placed ascending over each other. In the 
middle was a kind of foot-bank, or eminence, 
with obelisks, statues, and posts, at each end. 
This served them for the courses of their 
bigre and quadriga?. Those that have luea- 
C I s 
sured the circus say Unit it was 2187 feet 
long, and 960 broad; so. that it was ti e 
greatest building in Rome, borne sav it 
would contain 150,000 people, others 2(30,00® 
or 300,000. 'the circus was dedicated to 
the sun, as a little temple of the sun in till 
middle denoted. Some say that there we raj 
eight ciicuses in Rome, ot which several 
eith<J1 through vanity or devotion] 
built for the ornament of the city. 
CIRRI, among botanists, line strings oi 
tmead-iike filaments, by which some plants 
fasten themselves to walls, trees, Ac. Such 
are those of ivy. 
Cirri in ichthyology, certain oblong ami 
soft appendages, not' unlike little worms 
hanging from the under-jaws or mouths of 
some fishes. r l hose cirri, commonly transn 
lated beards, afford marks to distinguish (he 
different species ol the fish on which they are 
found. r l heir use may be to give notice of 
approaching danger or prey ; since by their 
hanging position, as well as by their soft tex- 
ture, they must be more sensible of anv mo-: 
tion m the water than any other part. 
CJ RSOCELE, or Hernia varicosa. 
See Surgery. 
CISSAMPELOS, a genus of the monadel- 
phia order, in the dioecia class of plants ; and 
in the natural method ranking under the 1 lth 
order, sarmentaceae. The male calyx is te-4 
ti aphyllous ; no corolla; the nectarium wheel-j 
shaped; four stamina with their filaments 
grown together, The female calyx is mono-' 
phyllous and ligulated, roundish, or like a 
piece of garter a little roundish. There is 
no coiolla ; three styles, find a monospennous 
berry. r l here are five species : the 
C issamplos caapeba is a native of the 
warmest parts of America. The root an- 
plied externally is said to be an antidote 
against the bites of venomous serpents. The 1 
plant being infused in water, quickly fills the 
liquor with a mucilaginous substance, which 
is as thick as jelly; whence the name of 
freezing wyth, by which this genus of plants 
lias been distinguished by the Brazilians. 
CISSOID, m geometry, a curve ofthe 
second oidei, first invented by Idiocies, 
whence it is called the cissoid of Idiocies. 
Sir Isaac Newton, in his appendix de ivqua- 1 
tiomim construct ione lineari, gives the fol- 
lowing elegant description of this curve ; and j 
at the same time shews how, by means of it, 
to find two mean proportionals, and the roots! 
of a cubic equation, without any previous re-1 
duction. Let AG (Plate Miscel. fig. 14) be 
the. diameter, and E the centre of the circle 
belonging to the cissoid; and from F draw F D i 
b P, at right angles to each other, and let.FP 
be — AG; then if the square PEL) be so] 
moved that one side E P alwavs passes 
through the point P, and the end'D of the ] 
other side ED slides along the right line] 
f U, the middle point C of the side E D will J 
describe one leg G C of the cissoid ; and by 
continuing out F D on the other side F, and 
turning the square about by a like operation I 
the other leg may be described. 
Ibis curve may likewise be generated by 1 
points in the following manner. Draw the 1 
indefinite right line BC (Plate fig. B) - lt 
right angles to A B the diameter of the semi- I 
circle A O B, and draw the right lines A If j 
A F, A C, &c. then if you take A M — LI]’ 
A O = OF, Z C=A N , & c. the points MOC’’ I 
tkc. will form the curve AMOZ of the cissoid’ ■ 
