American telegraph. [volume] (Washington [D.C.]) 1851-1851, 1851-07-08
MECHANISM, No. x.-Br JOSIAH uoLpnooK.

The sphere, cylinder, and cone are called
"the three round bodies" They are so called
frem the fact that most other round bodies may
be viewed as notifications of these The sphere
may be called the regular curved solid" 1t is
even more regular than either of the five regu-
lar solids already named. 1t has no distinction
of sides, edges, or corners 1t presents the
same view from whatever point examined. Ii
is a perfectly round body. By pressing and
rolling, the sphere may be changed into two
spheroids, flattened and heightened, called OBJ.
late and probate. The sphere and spheroids
can be readily illustrated and formed by putty
dough, clay, or any soft substance. The two
| spheroids are exhibited in many vegetables
The turnip, onion, peach, and canteloupe are
oblate spheroids. The plum and watermelon
| are probate spheriods. The earth is an oblate
spheroid, being very slightly fattened at the
poles.
A plane passing through the centre of a sphere
divides it into two hemispheres. These can be
divided again and again, presenting various in
teresting divisions of this interesting mathe-
matical solid. The cylinder is round body of
uniform diameter and circular ends. The cone
is a round body, with one end circle, the other
point, called the base and apex. The trunks
of trees and stems of grasses are cylinders, or
cylindrical; the carrot, beet, and parsnip are
cones
The cone can be divided in five different sec
tions, making by these divisions triangle,
circle, ellpse, hyperbole and parabola. The
properties of these figures so interesting as |
to be the subject of distinct science, under |
the title Of "Conic Sections" This science is |
sufficient in its details to occupy volume of
considerable size.
The three round bodies can be brought en-
tirely within the comprehension of young chill
dren, say six or eight years old, by the reyolu-
tions of four figures made of brass, tin, or iron.
The revolution of circle produces the sphere.
An eclipse revolving around its two dameters
produces the two spheroids, oblate and probate
square or oblong gives a cylinder, and
triangle the cone. These revolutions also give,
clearly and strikingly, some interesting facts
about the earth.
circle, by different divisions, shows a semi |
circle, quadrant, sector, segment, diameter, |
radius, chord arch, tangent, secant, sine, CO.
sine, &c, all important to be familiar at least
to every one engaged in business pursuit.
BY lathe any person can form, for his own
instruction and amusement, not only the three
round bodies, but innumerable notifications of
them, as called for in the daily purposes of
farming, mechanism, and domestic economy
No other instrument probably combines so
much utility, amusement, and taste. Many
literary and other sedentary personages provide
themselves with lathes; frequently the amuse-
ment of ladies as well as gentlemen; excellent
for boys, and girls, too.
ExPERMENTs.-In one building not thou
sand miles from Washington were two schools
In one, pupils were whipped daily and severely
for playing truant; in The ether they would
need whipping, If at all, 70 keep them from
school. The former was q Book School p
the latter "WorkinP Schooi using the hand
in aid of the mind