314 
CAT 
CAT 
Cat, or cat-head, on shipboard, a short 
piece of timber in a ship, lying aloft right 
over the hawse, having at one end two 
shivers, wherein is reeved a rope, with a great 
iron hook fastened to it, called 
Cat hook. Its use is to trice up the an- 
chor, from the hawse to the top of the fore- 
castle. 
Cat-holes, in a ship, are over the parts 
as right with the capstan as they can be : 
their use is to heave the ship astern, upon oc- 
casion, by a cable, or a hawse, called stern- 
fash 
Cat-gut, a small string for fiddles and 
other musical instruments, made from the in- 
testines of sheep and lambs, dried and twisted 
either singly or several together. They are 
sometimes coloured, and are used by watch- 
makers, cutlers, turners, and other artificers. 
Great quantities are imported intoEngland and 
other northern countries, from France and 
Italy. 
Cat-salt, a name given by our salt- 
workers to a very beautifully granulated kind 
of common salt. ' It is formed" out of the bit- 
tern, or leach-brine, which runs from the 
salt when taken out of the pan. When the 
common salt is taken from the boiling-pans, 
it is put into long wooden troughs, with holes 
bored at the bottom for the brine to drain 
out : under these troughs vessels are placed 
to receive this brine, and across them small 
sticks, to which the cat-salt lives itself in 
large and beautiful crystals. It contains some 
portion of the bitter purging salt, is sharp 
and pungent, and is white when powdered, 
though pellucid in the mass. Large quanti - 
ties ol this salt are used in the manufacture of 
hard soap. 
CA IACAUSTIC curves, in the higher 
geometry, that species of caustic curves 
which are formed by reflection. 
These curves are generated after the fol- 
lowing manner. If there be an infinite num- 
ber of rays, as AB, AC, AD, See. (see 
Plate, Misccl. fig. 12.) proceeding from the 
radiating point A, and reflected at any given 
curve BDH, so that the angles of incidence be 
still equal to those of reflection; then the 
curve BEG, to which the reflected ravs 
IT, CE, DF, & c. are tangents continually, 
as in the points I, E, F, is thecatacaustic 
curve. 
If the reflected IB be produced to K, so 
that AB = BK, and the curve KE be the 
evolute of the cataeaustic BEG, beginning at 
the point K ; then the portion of the cuta- 
caustic BE = AC — AB -j- CE — BI con- 
tinually. Or-if any two incident rays, as AB, 
AC betaken, that portion of the caustic that is 
evolved while the ray AB approaches to a 
coincidence with AC, is equal to the differ- 
ence of those incident rays -j- tire difference 
of the reflected rays. When the given curve 
is a geometrical one, the cataeaustic will be so 
too, and always rectifiable. 
The cataeaustic of a circle is a cycloid, 
formed by the revolution of a circle along a 
circle. T he caustic of the vulgar semi-cy- 
cloid, when the rays are parallel to the 
axis, is also a vulgar cycloid, described 1)) 
the revolution of a circle upon the same 
base. The caustic of the logarithmic spiral 
is the same curve, only set in a different 
position. 
CAT AC URESIS, in rhetoric, a trope 
CAT 
which borrows the name of one thing to ex- 
press another. 
CATACOMB, a grotto or subterraneous 
place for the burial of the dead. The term 
is particularly used in Italy for a vast assem- 
blage of subterraneous sepulchres, three 
leagues from Home, in the via Appia, sup- 
posed to be the sepulchres of the antienls. 
Others imagine these catacombs to be the 
cells wherein the primitive Christians hid 
themselves. Each catacomb is three feet 
broad, and eight or ten high, running in form 
of an alley or gallery, and communicating with 
one another. Some authors suppose them to 
have been the puticuli mentioned by Festus 
Pompeius, into which the Romans threw the 
bodies of their slaves, to whom they denied 
the honours of burying; and Mr. Monro, in 
the Philosophical Transactions, gives it as 
his opinion, that the catacombs were the bu- 
rial-places of the first Romans, before the 
practice of burning the dead was introduced ; 
and that they were dug in consequence of 
these opinions, that Shades hate the light, and 
love to hover about the places where their 
bodies were laid. 
T he catacombs of Egypt seem to be of a 
different nature, though called by the same 
name. The bodies found in these'catacoinbs 
are mummies. In searchingfor these labourers 
are frequently obliged to clear away the sand 
lor weeks together, before they find the pre- 
cious deposit. C pon coming to a square 
opening of about eighteen feet in depth, 
they descend into it by holes made for the 
feet, placed at proper distances, and there 
they are sure of finding a mummy. These 
caves, or wells, as they are usually called, 
are hollowed out of free-stone, which is found 
in Egypt a few feet below the covering of 
sand. At the bottom of these, which are 
about forty feet below the surface, there are 
several square openings on each side of the 
passages, of ten or fifteen feet wide, and 
these lead to chambers of fifteen or twenty 
feet square, hewn out of the rock ; and in 
each ot the catacombs are to be found several 
apartments communicating with one an- 
other. T hey are said to extend so far as to 
undermine the city of Memphis and its en- 
virons. In some of these chambers the walls 
are adorned with figures and hieroglyphics; 
in others the mummies are found in tombs, 
round the apartment, hollowed out in the rock. 
CATALEPSY, in medicine, a kind of 
apoplexy, or drowsy disease, in which the 
patient is taken speechless, senseless, and 
fixed in the same posture in which the disease 
first seized him. See Medicine. 
CATALOG UEo/ the stars. See Astro- 
NOMY. 
C AT AN AN CUE, Candia lion's foot, a 
genus of the poly gam ia wqualis order, in the 
syngenesia class oi plants, and in the natural 
method ranking under the 49th order, com- 
posite. The receptacle is paleaceous ; the 
calyx is imbricated ; the pappus furnished 
with awns by a ealiculas of live stiff hairs. 
There are three species, oi which the most 
remarkable is the 
Catanaiiche cerulea, which is a hardy, her- 
baceous, and very ornamental plant tor the 
flower-garden. There is a variety with dou- 
ble flowers. , 
CATAPITONICS, the science which con-' 
siders the properties of reflected sounds. See 
Pneumatics. 
CATAPIIRACTA, in antiquity, a kind of 
coat of mail, which covered the soldier from 
head to foot. Hence cataphractati were 
horsemen armed with the cataphracta, whose 
horses, as Sallust sayp were covered with 
linen full of iron plates disposed like feathers. 
CATAPHRY GIANS, antient heretics, 
who took their name from the country of 
Phrygia. They supposed the Holy Spirithad 
abandoned the church, and therefore that 
Montanus, as a prophet, and Priscilla and 
Maximilla, as true prophetesses, were to be 
consulted in every thing relating to religion. 
CATAPLASM, an external topical medi- 
cine, of a soft consistence, known by the 
common name of poultice, and prepared of 
ingredients of different virtues, according to 
the intention of the physician. See Phar- 
macy. 
CATAPULTA, in antiquity, a military 
engine contrived for the throwing of arrows, 
darts, and stones, upon the enemy. Some of 
these engines were of such force, that they 
would throw stones of an hundredweight. 
Josephus takes notice of the surprising effects 
of these engines, and says, that the stones 
thrown out of them beat down the battle- 
ments, knocked off the angles of the towers, 
and would level a whole file of men, from one 
end to the other, were the phalanx ever so 
deep. 
CATARACT, in hydrography, a precipice 
in the channel of a river, caused by rocks, 
or other obstacles, stopping the course of 
the stream, whence the wafer falls with a 
greater noise and impetuosity : such are the 
cataracts of the Nile, the Danube, the Rhine, 
and the famous one of Niagara in America. 
Cataract. See Surgery. 
CATARRH, in medicine, a defluxion 
from the head upon the mouth and aspera 
arteria, and through them upon the lungs. 
See Medicine. 
CATECHU, in the materia medica, im- 
properly called terra japonica in the shops, is 
a concreted vegetable juice, partly of the 
gummy, partly of the resinous kind. See 
Areca, and Materia Medica. 
CATEGORY, in logic, a scries 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 certain 
genera or classes ; and these classes the 
Creeks called categories, and the Latins pre- 
dicaments. Aristotle made ten categories, 
viz. quantity, quality, relation, action, pas- 
sion, time, place, situation, and habit, which 
are usually expressed by the following tech- 
nical distich. 
Arbor, sex, servos, ardore, refrigerat, ustos, 
Ruri eras stabo, nec tunicatus ero. 
C ATEN ARIA, in the higher gepmetry, . 
the name of a curve line formed by a rope 
hanging freely from* two points of suspension, 
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 James Bernouilli published 
it as a problem. Dr. Gregory, in 1697, pub- 
lished a method of investigation of the pro- 
perties formerly discovered by John Bernouilli 
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 catenaria. 1 . Suppose a line 
heavy and flexible, the two extremes of which . 
