CAT 
CATEGORY, in logic, a series or order 
of all the predicates or attributes contained 
under any genus. 
The school philosophers distribute all the 
objects of our thoughts and ideas into cer- 
tain genera or classes, not so much, say 
they, to learn what they do not know, as to 
communicate a distinct notion of what they 
do know ; and these classes the Greeks call- 
ed categories, and the Latins predicaments. 
Aristotle made ten categories ; viz. sub- 
stance, quantity, quality, relation, action, 
passion, time, place, situation, and habit, 
which are usually expressed by the follow- 
ing technical distich : 
Arbor, sex, servos, ardore, refrigerat, 
ustos, 
Ruri, craSf stabo, nec tunicatus eto. 
CATENARIA, in the higher geometry, 
the name of a curve line formed by a rope 
hanging freely from two points of suspen- 
sion, whether the points be horizontal or 
not. The nature of this curve was sought 
after in Galileo’s time, but not discovered 
till the year 1690, when Mr. Bernoulli pub- 
lished it as a problem. Dr. Gregory, in 
1697, published a method of investigation 
of the properties formerly discovered by 
Mr. Bernoulli and Mr. Leibnitz, together 
with some new properties of this curve. 
From him we take the following method of 
finding the general property of the cate- 
naria. 
1. Suppose a line heavy and flexible, 
the two extremes of which F and D, 
Plate II. Miscellanies, fig. 8, are firmly fix- 
ed in those points ; by its weight it is bent 
into a certain carve F A D, which is called 
the catenaria. 
2. Let B D and i c be parallel to the ho- 
rizon, A B perpendicular to B D, and D c 
parallel to A B, and the points B b infi- 
nitely near to each other. From the laws 
of mechanics, any three powers in equili- 
brio, are to one another as the lines paral- 
lel to the lines of their direction, (or in- 
clined in any given angle) and terminated 
by their mutual concourses : hence if D d 
express the absolute gravity of the particle 
D d, (as it will if we allow the chain to be 
every way uniform) then D c will express 
that part of the gravity that acts perpendi- 
cularly upon Dd; and by the means of 
which this particle endeavours to reduce 
itself to a vertical position ; so that if this 
lineola dc be constant, the perpendicular 
action of gravity upon the parts of the chain 
will be constant too, and may therefore be 
CAT 
expressed by any given right line. Fur- 
ther, the lineola D c will express the force 
which acts against that conatus of the par- 
ticle D d, by which it endeavours to restore 
itself in a position perpendicular to the ho- 
rizon, and hinders it from doing so. This 
force proceeds from tlie ponderous line D A 
dravving according to the direction Dd; 
and is, cecteris paribus, proportional to the 
line D A which is the cause of it. Sup- 
posing the curve FAD, therefore, as be- 
fore, whose vertex is A, axis A B, ordinate 
B D, fluxion of the axis D C = B 6, fluxion 
of the ordinate d c, the relation of tliese two 
fluxions is thus; viz. dc:Dd:;a:DA 
curve, which is the fundamental property 
of the curve, and may be thus expressed 
(putting AB = a: and BD=y and A D 
CATERPILLAR, in natural history: 
the larvas of butterflies are universally 
known by the name of caterpillare, and are 
extremely various in their fonns and co- 
lours, some being smooth, others beset with 
either simple or ramified spines, and some 
are observed to protrude from their front, 
when disturbed, a pair of short tentaeula or 
feelers, somewhat analagous to tliose of a 
snail. A caterpillar, when grown to its 
full size, retires to some convenient spot, 
and securing itself properly by a small quan- 
tity of silken filaments, either suspends it- 
self by the tail, hanging with its head down- 
wards, or else in an upright position, with 
the body fastened round the middle by a 
number of filaments. It then casts off ca- 
terpillar-skin, and commences chrysalis, in 
which state it continues till the biUtcrfly is 
ready for birth, which liberating itself from 
the skin of the chrysalis, remains till its 
wings, which are first short, weak, and co- 
vered with moisture, are fully extended, 
this happens in about a quarter of an hour, 
when the animal suddenly quits the state of 
inactivity to which it had been so long con- 
fined, and becomes at pleasure an inhabi- 
tant of the air. 
C.-xTESBAlA, in botany, so called in ho- 
nour of Mark Cate^by, a genus of theTetran- 
dria Monogynia class and order. Natural 
order of Luridae. Rubiacese, Jussieu. Es- 
sential character: corolla monopetalous, 
funnel-form, extremly long, superior; sta- 
nvens within the mouth ; berry polysper- 
mous. There are but two species, of which 
C. spinosa, lily^thorn, rises with a branch- 
ing stem to the height of twelve feet, co- 
vered with a pale russet bark; the branches 
