CYL 
tation Las moderated, is the only proper 
mode of removing the impurities. 
We are concerned to state, that those 
kinds of apples which were so long famous 
for yielding a fine stum, are much on the de- 
cline ; and that no means have hitherto 
been discovered of preventing the untimely 
decay of the trees. It is to be hoped, that 
we shall either receive some fresh grafts 
from the continent, or that some ingenious 
person will devise the means of preserving 
what we have from the canker ; which de- 
stroys our best orchards after a few years 
of growth. 
Explanations of Plate IV. Miscel. fig. 3. A 
shews the vertical section of the stone roller, 
with its axis C, C. The suggested improve- 
ment consists in rounding its edges, and in 
suiting the bottom of the trough B, B, B to 
that shape. 
Fig. 4, shews the side of the wheel, half- 
way buried in the trough, of which L is 
the upper line, and K K the bottom. The 
arm E moves freely on the axis F, and is 
fastened at C, by a hinge, to the board H H ; 
which is kept in its place, on the surface of 
the trough, by the pins 1 1 j of which there 
are two on each side. Thus as tlie wheel 
(or stone) D, revolves, at whatever height 
the board will maintain its position. If too 
light, it may be loaded. 
Fig. 5, shews the two cylinders, with 
their manner of locking into each other ; 
one crank turning both ; the teeth o, o, 
fitting into the mortices p, p. The wheels 
M and N, having by this means, contrary 
inotions, catch the apples between their ap- 
proaching surfaces, and by aid of the teeth 
crush them into small pieces ; which are re- 
duced to a -perfect pulp as they pass be- 
tween the rollers, into the vessel below. 
X is the handle of the winch. 
This machine, fig. 5, is in common use in 
the west of England, and is found to answer 
welL 
CYGNUS, in astronomy, a constellation 
of the northern hemisphere. See Astro- 
nomy. 
CYLINDER, in geometry, a solid body, 
supposed to be generated by the rotation 
of a pai’allelogram. If the generating pa- 
rallelogram be rectangular, the cylinder it 
produces will be a right cylinder, that is, 
it will have its axis perpendicular to its 
base. If the parallelogram be a rhombus, 
or rhomboides, the cylinder will be oblique 
or scalenous. 
Cylinder, properties of the. i. The sec- 
tion of every cylinder by a plane oblique to 
CYM 
its base, is an ellipsis. 2. The superfices of 
a right cylinder is equal to the periphery of 
the base multiplied into the length of its 
side. 3. The solidity of a cylinder is equal 
to the area of its base, multiplied into its al- 
titude. 4. Cylinders of the same base, and 
standing between tlie same parallels are 
equal. 5. Every cylinder is to a spheriod 
inscribed in it, as 3 to 2. 6. If the alti- 
tudes of two right cylinders be equal to the 
diameters of their bases, those cylinders are 
to one another as the cubes of the diame- 
ters of their bases. 
To find a circle equal to the surface of a 
cylinder, we have this theorem : the surface 
of a cylinder is equal to a circle, whose ra- 
dius is a mean proportional between the 
diameter and height of the cylinder. The 
diameter of a sphere, and altitude of a cy- 
linder equal thereto, being given, to find 
the diameter of the cylinder, the theorem 
is, the square of the diameter of the sphere 
is to the square of the diameter of the cy- 
linder equal to it, nearly, as triple the alti- 
tude of the cylinder to double the diameter 
of the sphere. 
CYLISTA, in botany, a genus of the 
Diadelphia Decandria class and order. Na- 
tural order ofPapilionacese or Leguminosa*. 
Essential character ; calyx very large, four- 
parted ; the upper division cleft at the end ; 
corolla permanent. There is but one spe- 
cies, viz. C. villosa, haiiy cylista. It flow- 
ers in April and May ; was introduced in 
1776, but from what country is not known. 
It is a shrub, and requires the heat of the 
stove to preserve it. 
CYMBACHNE, in botany, a genns of 
the Polygamia Monoeeia class and order. 
Natural order of Gramina, or grasses. Es- 
sential character : inflorescence half spiked j 
herin. ealyx two-glumed, one-flowered, 
parallel to the rachis; outer valve linear, 
the opposite boat-form ; female calyx one- 
glumed, ovate, opposite to the rachis. One 
species, viz. C. ciliata. This is a slender 
grass, a foot in height, with several culms, 
simple or branched, with a single leaf, or 
leafless. It is found in Bengal. 
CYMBAL, a musical instrument in use 
among the ancients. The cymbal was 
round, made of brass, like our kettle-drums, 
and, as some think, in their form, but 
smaller, and of different use. 
CYM B ARIA, in botany, a genus of the 
Didynamia Angiospermia elass and order. 
Natural order of Personatae. Scrophula- 
rim, Jussieu. Essential character: calyx 
ten-toothed; capsule cordate, two-celled. 
