The Arizona sentinel. [volume] (Arizona City [Yuma], Yuma County, A.T. [Ariz.]) 1872-1911, 1889-03-02
CENTER OF GRAVITY.
An Instructive Article on an Interesting
Scientific Subject.

An Instructive Article on an Interesting
Scientific Subject.
The center of gravity is that point
about which all parts of a body will
balance each other, no matter in what
position the body may be placed If the
body be symmetrical with regard to
every axis, that is if every right hand
part has left hand part exactly cor
responding to it, and every upper part
a lower, and every front part CORE
spending back, then the center of
gravity will be at the center of bulk,
if, too, the body be of the same spe-
cific gravity all the way through.
The existence of such center was
discovered by Archimedes. The fact
that the center of gravity of the earth
is practically its center of bulk, makes
all plumb lines point to about that
center; and all of them practically to
the same point. This being the case,
we bear in mind that no two plumb
lines are or can be parallel; and that
if there be very long and very high
dlO UObn vi 1Go wv " 0uu w dllS
are plumb" that building will be
longer at the top than it is at the bot
tom. Take for instance the Main Cen
tennial building in Philadelphia, which
building was about 1900 feet long.
Suppose a case very far from the fact,
that it had been 500 feet high, (Which
is not so high by So feet as the Wash
ington mOnument) then, upon the sup
position that the earth is 1900 miles in
diameter. the top would have been 052
inches longer than the base.
This can be figured up in this way.
A diameter of Z, 912 miles gives aradius
of 1856 miles. equals 20, S87, $50 feet
The top would be in length a0aS9e5a- S99
times the base; and with base of 800
feet that would make 2HSH1sgI1 sos.sSs5 z =
0.52 inch, nearly. 1t is not very much
to be sure. Yet it is there for all that
Almost every one has heard the story
of Columbus and the egg; but it is not
every one who calls to mind that there
are three ways of making an egg stand
upon either end. The way attributed
to Christopher Colombo, or Cristobal
Colon, or Christopher Columbus, mar
iner of Genoa. was to tiatten the egg
a trife at one end, so as to offer resist
ance to its tipping. That is not at all a
neat way A little gum arabic or 9TH
er cement would accomplish the same
result. The other and more scientific
way is to shake the egg violently until
the yelk case is broken, when the yelk
will settle down to whichever end you
wish, and, by it's greater weight, lower
ing the center of gravity of the COM
pound mass, will keep the egg in stabl"
equilibrium.
A very pretty experiment not record
ed in all the text books is that in which
a ball apparently rolls up hill by the
action of gravitation. Two long cones
are placed with their points together
and the bases near together; a ball
placed upon them near their tips rolls
toward their bases, which is apparent
ly up hill, if viewed from the side; but,
viewed from the butt ends of the cones,
the ball is seen to be rolling down hill.
The most difficult forms of body to
overthrow are the pyramid and the
cone, the center of gravity having to be
raised so far before the body can be
overthrown. Cor, Mechanical News.