The southern press. [volume] (Washington [D.C.]) 1850-1852, 1851-06-21
Mechanism, No. vIH.--By Josiah HoIbreok

In mathematics an empty cask and stick Of
timber are both solids also, a lumber of water
and bar of iron, an empty room and a block of
granite, cave and mountain, a perfect vacuum
and mass ofpatna. The terms air, gas, vapor,
liquid, and vacuum have no place in pure mathe-
matics; they belong to chemistry. ANY figure
with length, breadth, and thickness is mathe-
NAUTICAL solid. Five such figures are called "re-
gular solids" Three of these are enclosed in
equilateral triangles. Their respective number
of sides are four, eight, and twenty; and they
are hence called tetraedron, ocaedron, and icosa-
edron. One ofthe five is enclosed in six squares,
and is hence called hexaedron, or, more CON-
monty, cube. The remaining one of the five
is enclosed in twelve pentagons, or five-sided
surfaces, and called dodecaedron OF each of
the "ive regular solids" the sides, corners,
and edges are all alike. No matter which side,
corner, or edge is presented to the eye, the APP
pearance is the same. This is true, and can be
true of no other plain figure but one of the re-
gular solds-a fact of great Importance in the
subject of mechanism
Not long since chemist paid carpenter nine
dollars for set of regular solids, made of some
commorW wood, say two or three inches in diane
ter. Thousands have been made by children
as their richest amusement, far superior in manv
respects, and much more instructive, from beino
made by the pupils own hands Being made
of poseboard, the outspread surface is seen
showing the mode of combining, as we'll as In,
solid in its regular form.
Not long since a box containing the cube
modified by several sections and combinations
was procured from France, at the cost of 81,
dollars. Last winter girl seven years old, the
daughter of member of Congress, made. prin.
cipally under the instruction of another prl q,
ten years old, set of illustrations far NOR,
complete in ehecting their object than those
procured from France, though in workmanship
inferior of course. Topupil and teacher. il need
not be said, the work was amusing instruction
and instructive amusement. With the cube. nm.
der several divisions and combinations, the other
regular solids, variously modified were also
formed by the same young pupil, aided by her
] juvenile teacher
BY these practical lessons the facts that in M,
inch cube are eight half-inch cubes that in a
two-inch cube are eight inch cubes; and that in
a four-inch cube are sixty-fo inch cubes, and
the whole principle of the ratio of increase in
all solids, become as familiar both to teacher and
pupil as that lead is heavy and cork light, or any
other physical truth learnt by repeated expert
ments. The doctrine of the cube, thus famiarly.
because practically and agreeably learnt, is of
'cfy Sicat iipoithhcc, us pei1g AT t0e fOun0atlOn
of thousands of daily business operations, with
that importance greatly increased from the con-
slant and gross blundvs in business, arising
from the general ignorance of this fundamental
principle of cubic measure even among our
mostintelligent business men. The five regular
solids together are at the foundation of the
beautiful, wonderful, and instructive science OF
crystallography, as they are of natural and arti
fetal mechanism generally, as exhibited in the
works of God and man. One or two hundred
dollars are frequently paid for models Of erys-
tails imported from France.
ExPERmENT--The clerk of steamboat once
charged for pile of rope for. passing cars on
an inclined plane, according TO his measure
ment, one-fourth of the price intended; not hav
ing learnt the difference between an eightfoot
cube and eight cubic feet, or other mysteries of
the cube--also locked up from thousands to
whom i would be well if they were spread out
in broad daylight