Omaha daily bee., 1915-11-17

affords an especially vivid conception OF
the way gravitatlon works, a thing about
which even many educated people appear
TO have very confused ideas.
! Assume that the shaft runs through the
center Of the earth. Also. in order 10
avoid bubbles. suppose the earth 70 be
perfect, smooth. homogeneous sphere.
and neglect the effect upon a falling
body of the eRrth's rotation around its
axis The car would descend. az far as
the center. in the same manner that an
! ordinary passenger lift descends from the
top OF building, being drawn down by
the force of gravity, or the attraction
OF gravitation.
Every particle of matter In the earth
exercises it's share OF this force by pull
ing toward itself, but the aggregate Of
feet OF all these small forces lie a single
pull toward the sarths center.
The amount OF this pull upon any body
Is measured by what We call weight. The
weight increases or decreases not merely
with the size. but with the density OF
the body. because the pull Of gravitation
Ia exercised equally upon every particle
that the body contains, and dense
body contains moro particles than a rare
or light body. Consequently an iron can
non ball weighs more than a wooden
bowling ball OF the same siso
Now we come to very interesting
point. As long as the oar remained on
the surface, every particle In the earth
would pull It toward the center The
majority OF the particles do not pull d.
reetly toward the center with their en-
time attractive force. but a greater or
lesser portion OF the attraction Of each
particle Ia toward the center. and az be-
fore said, the aggregate. outstanding eff
feet of all these forces united 10 4 single
pull to the center.
But when the car had descended be-
low the surface all the particles compos-
ing that part, or shell, OF the earth sit
uated above the level Of the car. would
cease to exercise a pull toward the CEN
ter. and their various attractions, as
Newton Mechanically demonstrated.
would balance or neutralize one another
In such manner that they would no
longer affect the movement OF the car.
The practical result would be that the
aggregate downward pull on the car
would proportionately diminish.
As tho car continued to descend the
thickness Of the shell OF earth above
its level would increase. and consequent
ly the downward pull would decrease,
until when II reached the center there
would be no pull at all, the forces Of
attraction being balanced against one
another on all sides. Hero, then, the
strain upon the cable supposed to regu-
late the velocity OF the cars descent
would cease entirely, because the car
and everything that Il contained. would
lose their weight. A passen-
ger in the car would lose all sense OF
direction. There would be for him neither
up nor down. He could not stand or fall |
He could however still use HE muscu- |
lar strength, and might. by a push. OF |
a kick, set himself spinning like a |
thistle down in the wind But II he |
Lried to walk he would bound away like |
a rubber ball at the first stepl
In order to continue the trip of the !
'ar up on the opposite surface of the |
'arth II would be necessary to reverse
he action OF the cable so that now Il |
would lift against the force OF gravity. 4
As soon as the car was drawn away |
rom the center the sense OF up and |
Town would come back TO the passenger.
What had before been the ceiling would /
low become the floor. The weight would 1
Increase with increase OF distance from
The center. and the strain upon the
able would grow gradually until the
IurfRoe was again reached.
Emerging on the other side of the |
'arth from that which he had left, the
would have his feet pointing
n exactly the opposite direction from
hat 70 which he had been accustomed Il
N the other sidei but he would be to-