CON 
the operation of cutting for the stone, and 
in laying open sinuses and fistulas. 
Conductors, in electricity, are long me- 
tal rods, whose points are raised so high as 
may be convenient, above houses, &c. for 
the puipose of attracting or receiving the 
electric fluid, and of conducting it into the 
earth, or into water, thereby to prevent tite 
building from being struck by lightning. 
To effect this, the rod should be detached, 
and its point should be sharp; by which 
mean the electric fluid will be silently dis- 
charged. If the conductor is allowed to 
lay along the wall of the house, or that it 
is blunt, instead of being pointed, at its 
summit, it will attract the lightning, which 
in such case will do more or less damage to 
the building. Thus the rod should be kept 
from the walls, &c. by pieces of well-sea- 
soned wood, coated with resin, or of lead, 
which as well as glass, sealing-wax, sulphur, 
bees'-wax, oil-water, &c. are all non-con- 
ductors while cold; though, when heated 
to a great degree, they become conductors. 
The rod should pass freely from the top of 
the building to the ground, without the line 
of its continuity being any where broken. 
It is found that black lead is an excellent 
aid, both tO’ affix as a sharp point to the 
apex, and to be laid at a few feet deep in 
the earth where it is moist, and surrounded 
by a bed of charcoal. The rod should pass 
into the mass of black lead, vi'hich will 
cause the electric fluid to be extinguished. 
Where buildings are extensive, and es- 
pecially where there are many high chim- 
neys, turrets, &c. two or more conductors 
should be used ; else tire electric fluid, in 
its passage from a charged cloud, may be 
intercepted by such heights, and do consi- 
derable injury. Trees standing single on 
plains are very dangerous conductors, as are 
those lofty trees that rear their heads con- 
spicuously in large woods. Hence we so 
often see them rent to pieces by lightning, 
and such cattle as take refuge under tliefr 
inviting shelter destroyed. Walls are con- 
ductors when lightning has entered a room ; 
therefore all persons should avoid sitting 
near them during thunder storms ; and in 
countries where lightning is frequent, care ■ 
should be taken to remove iron bars, &c. 
For the various amusing and interesting 
matter^ relating to Electricity, we must 
refer the reader to that article and to Gal- 
vanism. 
CONDYLOMA, in medicine, a tuber- 
cle or callous eminence which arises in the 
CON 
folds of the anus, or rather a swelling or 
hardening of the wrinkles of that part. 
CONE, in geometry, a solid figure, hav- 
ing a circle for its base, and its top termi- 
nated in a point or vertex. 
Cone, Properties of the, 1. Cones and 
pyramids having the same bases and alti- 
tudes are equal to each other. It is shewn, 
that every triangular prism may be divided 
into three equal pyramids, and therefore 
that a triangular pyramid is one third of a 
prism standing on the same base, and hav- 
ing the same altitude. Hence, since every 
multangular body may be resolved into tri- 
angular ones, cvejy pyramid is the third 
part of a prism standing upon the same base, 
and having the same altitude ; and as a 
cone may be esteemed an inflnite angular 
pyramid, and a cylinder an infinite angular 
prism, a cone is the third part of a cylin- 
der which has the same base and altitude. 
Hence we have a method of measuring the 
solidity and surface of a cone and pyramid. 
Thus, find the solidity of a prism or cylin- 
der, having the same base with the cone or 
pyramid, which found, divide by three, the 
quotient will be the solidity of the cone or 
pyramid. Or the solidity of any cone is 
equal to the area of the base, multiplied 
into one third part of its altitude. As for 
the surfaces, that- of a right cone, not taking 
in the base, is equal to a triangle whose 
base is the periphery and altitude the side 
of the cone ; therefore the surface of a right 
cone is had by multiplying the periphery of 
tlie base into half of the side, and adding 
the product to that of the base. 
2, The altitudes of similar cones are as 
the radii of the bases, and the axes likewise 
are as the radii of the bases, and form the 
same angle with them. 
3, Cones are to one another in a ratio 
compoimded of their bases and altitudes. 
4, Similar cones are in a triplicate ratio 
of their homologous sides, and likewise of 
their altitudes. 
fi. Qf the cones standing upon the 
same base, and having the same altitude, 
the superficies of that which is most oblique 
is tlie greatest, and so the superficies of the 
right cone is the least ; but the proportion 
of the superficies of an oblique cone to that 
of a right one, or which is the same thing, 
the comparison thereof to a circle, or the 
conic sections, has not yet been determined. 
Cones of the higher kinds, those whose 
bases and sections parallel to the bases, are 
circles of the higher kinds. They are gcjie- 
