Evening star. [volume] (Washington, D.C.) 1854-1972, 1929-04-30
TELLING THE TIME
THROUGH AGES NOW
|. SMITHSONIAN UNIT
Exhibit Shows Many Devices
for Determining How
Day Is Passing.
COLLECTION GOES BACK
TO OLD SHADOW STICK
Sun, Water and Sand Dials Dis
played as Predecessors to Mod
ern Accurate Clocks.
BY THOMAS r. HENRY.

ANSNtAoVA 0NtC0 Ny t1lC CANAcAOIL Va N1N~
chanical Technology of the Smithson-
ian Institution
The record extends from a stick
placed upright in the snow by the
MontagnaiS Indians of Canada, who
could read time crudely from the angles
of the shadow, to the latest improve
ments of American clock and watch
makers and the determination of time
to the thouSandth of second by the
Naval Observatory.
The earliest time-telling method, ac-
cording to the Division of Anthropology
which is cooperating In the exhibit,
was by observation of the shadows cast
by specific natural objects, such as trees
and rocks When men began to settle
in communities the need arose for a
standard time for everybody. This re-
suited in the first town clocks"-tall
shafts in some central location the
position of whose shadows at different
hours and seasons was observed with
some accuracy. The Egyptian obelisk,
and weighing 200 TONS probably was
an early example, serving also as a
commemorative shaft to some god.
Steadily Improving Dials.
From this point on. the collection
contains a steadily improving line of
sun dialS, many of which displayed
great ingenuity. Besides the large sun
dial set in gardens or public squares,
pocket instruments comparable to mod
ern watches came into use during the
middle ages. These appeared in Ger
many during the fifteenth and sixteenth
centuries. A pocket dial consisted of
aI
symbols, hinged at one end and con-
nected at the other by thread When
the device was opened and placed in
the sun, the time could be told by the
position of the threads shadow on the
bottom surface The accuracy depend
ed greatly on the fineness of the thread.
Some of these pocket dials were quite
elaborate, combining a compass and
marked with star signs and tables by
which the carrier could interpret the
threads shadow according to the sea-
son. All were cumbersome compared
with the heaviest of modern watches.
The fact that they were worthless at
night early led inventors to seek some
other way of telling time.
The most primitive method used In
the exhibit of the direct ancestry of
the modern clock was the sinking dish.
uaIlt11 DdCk 10 tUuU d. ~, IL COllSlstEu
of brass dish with tiny hole in the
bottom. which was placed in a pan of
water 1t would fill and sink in fairly
uniform time interval. An attendant
watched it constantly. Every time it
sank he emptied and replaced 1t. at the
same time striking a gong to denote
the time.
"Water Thief" Comes Along.
From this Greece and Rome came to
clepSydra, or water thief" A uniform
stream of water through funnel fell
into brass cylinder in which was a
wooden float with an upright pole at
tached to it. The pole was marked
with time symbols. AS the water rose
in the cylinder the pole protruded far
ther and farther above the surface and
the time was read from the markings.
The next step was to attach pulley
with a lead weight to the ascending
and descending pole. This pulley was
used to turn the hands on dial, SO
that time could be read from a dis
lance In the pulley was the germ of
the clock idea The water clock told
time with reasonable accuracy under
uniform conditions, but it was greatly
affected by changes in temperature.
Julius Caesar in one of the Gallo CAM
paigns flew into rage one morning
when he found the cylinder of the
clepsydra in front of his tent was a
mass of ice On hot Summer days the
water evaporated too quickly.
Sand DiaIs Mex. Device.
So the water clocks were replaced by
sand dials. The flow of sand was just
as uniform as that sof water and was
not changed by temperature. 1t was
not so easy to operate dial mocha
nism by the flow of sand and sets of
| them were necessary for the ordinary
| operations Of life. The exhibit contains
tiny dials set for boiling eggs and an
other which old-time clergymen used
| to keep on their pulpits TO time their
sermons. Some were quite elaborate, as
one set of four mounted in a revolving
| frame, which was used in fourteenth
century Germany. The inaccuracy OF
! the sand dial is revealed by modern
| tests of this instrument, which show
that the flow through the different dials
was not uniform by from two to eight
! minutes.
The principle OF the modern clock is
! credited to Gallileo, who observed a
/ swinging chandelier in a cathedral at
Pisa and timed the swings with his
! pulse finding that the time of each
swing was uniform. From this discov-
cry of the time keeping value of the
| pendulum the construction of clocks
spread through Germany and Italy
| The earliest were huge timepieces SET
| in the towers of town halls or cathe-
drals, often decorated very deliberately
From this point the exhibit shows a
| steady succession of better clocks. many
, of which have been loaned by George
Fl. Kernodle of Washington, long an
enthusiastic clock collector These in
clude such curiosities as q Japanese
clock of 1890. The hour and minute
signs are on vertical plate. on which
q marker moves up and down. Under
this system Of timekeeping the 24-houl
period was divided into two parts, night
and day, each 6 hours long. There was
a series of vertical plates, one for eaci
season. In Europe one of the earliest
was the Dutch chamber clock. which
combined the germ of the modern alarm
clock, gong sounding continuously
when certain time was reached An
other Is the bird-cage clock of Eliza.
bethan England. and another Frencf
iron clock, whose dial revolved to meet
the hands, which remained stationary
Some Cases Valuable.
Until early in the nineteenth centur,
clocks in the United States either wert
imported or made by individual clock.
makers who had learned their trade
abroad Sometimes they contracted
only to make the works, the purchases
hiring cabinetmaker to complete thu
job Some OF the artistic designs turned
out now are very valuable, such as thu