The Washington times., 1924-10-29


~ information about the va
IA rious ways Of measuring
time that men have invented.
This is OF interest to everybody,
for not only is time our most
precious possession, but upon It's
accurate measurement our whole
civilization is largely based.
The greatest. oldest and best
clock Is the rotating earth. which
makes the heavens appear to
turn round us like movable
dial. II the earth stood still on
its axis we should have no clear
idea Of time, s,icn as we now
possess. But it takes an astron-
omer, with his instruments, to
read this clock.
The first measure of time that
men employed was the length Of
the day, between sunrise and
sunset. But when they tried to
divide 1t into twelve shorter
periods, or hours, they found out
two things-first, that If they
would keep the same number of
hours for the measure of day
they must make them longer In
summer and shorter in winter.
and, second, that If they wished
to have the hours always of equal
length they must count more OF
them a day in summer than In
winter. They might have divided
las they did eventually the
whole period OF one day and one
night into hours of equal length,
whose number would never vary,
but the first men were not as
tronomers, and had no means of
accurate observation Of the stars.
1t was the daylight hours that
were important to them.
FIRST TIME-PIECES.
In order. then, to get an un.
varying measure for short periods
Of time they had to use their
inventive faculties and contrive
some kind Of a clock. The earliest
devices Of this kind were clep-
sydras, or water-clocks. A water.
clock. in it's simplest form. con-
sists Of an upright vessel with a
small hole in the bottom to let
the water gradually escape, and
marks to show how tar the water
has descended in given time.
But here difficulty was en-.
countered Immediately. The
rapidity of the outflow varies
with the depth of the water; con-
sequently the water will descend
farther in a given time at the
beginning than at the end. To
avoid this either the distance be.
tween the marks must be care
fully varied, or else the vessel
must be made in the shape of an
inverted cone, smaller at the bot.
tom than at the top, so that as
the pressure diminishes the
quantity of water that must flow
out in order to lower the surface
equally In equal intervals is pro.
portionately diminished.
The ancients succeeded, very
well in overcoming this difficulty,
and they made clepsydlas Of
many ingenious forms. which
could even be employed for as
Economical observations. The
hour-glass is kind IT clepsyCra
in which sand takes the place Of
water
Gravity Clocks.
Alfred the Great invented a
candle clock, He had his candles
so proportioned that they would
burn down three inches per hour.
Plato, the philosopher, invented
a clepsydra which caused flute
to play at the end Of every hour,
so that the time could be told at
night
Haroun.al.Raschid sent to Char
lemagne as present clepsydra
in which the falling water opened
a little door at the end Of every
hour and caused number Of
balls, corresponding with the
number Of the hour, to fall upon
a brass drum. Az noon and at
midnight twelve miniature horse
men pranced forth and shut all
the doors for a new round.
After the clepsydra came the
gravity clocks, In which a weight
Is made to turn a system OF
wheels which move the, hands
over the dial. 1t was only after