Idaho County free press. [volume] (Grangeville, Idaho Territory) 1886-current, 1896-11-27
WEIGHT OF THE WORLD.
How II IL Calculated by an Enr.
nsh Professor.
Figures Which Are Bewildsrine in Thai,
Amnensity - The Scientific Gsntle-
man Ii Doubtless Safe from
Contradiction.

MN - DouDtieoe Safe from
Contradiction.
When Newton set himself tc and the
law BY which an apple falls to the
earth and the planets revolve ut vary
ing speeds along their orbits he con.
structed formula which would ex.
plain these phenomena, says the Lon
don Graphic. He laid it down as n law
that the force with which the earth At
tracts the apple or the apple the earth,
or the planets one another, is equal to
the mass of the one multiplied by the
mass OF the other, and divided by the
square OF the distance between them
the whole multiplied by q constant
called G. G is the Newtonian constant
OF gravitatiOn. 1t is Of all the con-
stants the most important to physical
science; 1t is a constant for the moro
accurate determination OF which PROT
Boys, who lecturcd upon it recently ut
the London institute, has been willing
to spend five years of the most arduous
and minute observation. 1t is one hum
dred years since Rev. Mr.. Mitchell first
devised an instrument by which it
would be possible to obtain, by actual
observation, the attraction which two
bodies have for one another.
Cavendish improved upon Mitchell's
observations, Cornu carried it on. Prof.
Boys has, SO to speak, carried it two
decimal places further. Now let us
consider how it would be possible to as
sertain, by observation, the attraction
which two bodies have for one an
Sther. II Prof. Boys were to hang q
,ouple of ffty-pound lead balls by two
1bers he would find it as impossible to
measure the inclination of the two
dbers to one another as to weigh q
sunbeam. But there is possible way
of measuring the attraction, and Prof.
Boys has made it more possible--or, let
US say, more practically the employ
ment of quartz fbers to suspend some
Of the balls he uses. He uses in all
four balls-two gold balls, a quarter of
an inch in diameter, weighing forty or
fifty grains, and two lead balls, four
and half inches in diameter, and
weighing each sixteen pounds. d. LII
Nov, suppose these four balls in
their first position suspended in one
plane. The two little gold balls are
suspended by quartz fbcrs on either
side Of an oblong mirror, to which they
are attached. If any force were to
pull one gold ball q little way. forward,
| and at the same time to pull the other
little gold ball little way back, it IL
| obvious that Q twist, an oscillation,
would be impaired to the tiny mirror
Now SO beautifully is this mirror, with
Its gold balls, hung on its tube, that q
force equal to the hundrcd-millionth
| part of q grain will set it swinging.
With this degree of sensitiveness at
tanned, we begin to get near some
means Of measuring influences upon it.
The influence we can measure is that
of the two lead balls. We imagined
them TO be, in the first instance, in the
same perpendicular plane as the little
gold balls Suppose we move them
contemporaneously and coequally, SO
that one lead ball moves in front of one
gold ball and the other lead ball moves,
exactly in the same way, behind the
other gold ball. If the hanging of the
mirror and its gold balls is deli"atc
enough it is obvious then that the force
exerted by the attraction between tho
gold balls and the lead balls will give
the mirror to which the gold balls are
attached little twist and will set II
oscillating. The instrument is del
icate enough.
Seated eighty feet away the observer
can time it. He therefore can measure
the force which the lead balls and thu
gold balls exert upon one another; HI
can measure the distance which thu
balls IRE apart; he can measure thu
balls. Therefore, knowing the force
the masses and the distance betweei
them, he can determine the great con
slant G, and, knowing G., he can deter
mine the specific gravity of the earth
he can find its weight. Prof Boys
after years Of experiment, has foun'
the specific gravity of the earth to b
5,527. Before this time we were con
tent to regard it rs SIS. He has take
Eve years or more to establish bcyon
controversy these other two decimals
People with taste for large figure
NAV be interested to hear that, takin
i this as basis, the weight of the worl
d may be taken Us $3.50 ZOO, 000, 000, 600
600, 900 tons.
That, as far as the present writer
z concerned, is the most lucid explain;
tion which can be given of Prof. Boy
method. But it has left untold the e.
traordinary mjnuteness of the observ,
lions and the sensitiveness of his II
struments. The instrument which col
. tains the system of gold and lead bal
is put in the corner Of an undergroun
crypt in Oxford. There is too muc
tremor of the earth in London. 1t
- boxed up in thick octagonal woode
box. 1t is separated from the observe
. by a series of felt curtains. He 81
eighty feet away and examines
movements by means Of a telescol
through Sits in the felt curtains and
the wooden box, and in the metal tub
holding the gold ball system.
The mirror reflects nine-foot sea
with 5000 divIs ions placed behind Il
observers head. In order to avoid CT
ating currents of mir, Prof. Boys h
", y, the scale illuminated only by lit
travelling lamp. In order to avo
tremors of earth he works at dead
n night, for o train shunting q mile aw,
will move that tiny mirror; and on
an earthquake in Transylvania, on Il
other side Of Europe, was marked
it. And then as to the measurement
II tho distance of the lead balls fro
| one another Is calculated by micr
L oxc. n,,l vv,;croocoy,a IN the 9(0th m