Evening star., 1914-12-27

in heavy bell jar, and n uniform
temperature is maintained at S4 de
grees. The variation from that in the
past year was only four-tenths of /;
tanned also, some Of the air being
pumped out of the bell. Corrections
in the clock are made by varying the
air pressure. An electric device keeps
the instrument wound up.
In the timeroom Of the observatory
located on the ground floor of the ad-
ministration building, is the sending
clock, which. while good one. is not
vault. 1t therefore has to be adjusted
exactly before sending out the time
signal Hence it and the standard
clock are put on a relay which con-
of both clocks is recorded and the diff
ference measured by a special scale.
Before making the comparison the
rate is applied to the standard clock
to bring it up to the time of compari-
son and the resulting sidereal time is
mean solar time. The difference of
longitude between the observatory and
the 18th meridian is also applied TO
convert this into standard time. After
all this is done the pendulum of the
transmitting clock is accelerated or re-
tarded with a tiny hairbrush until its
beat, as shown on the chronograph,
corresponds to the correct time.
Five minutes before the hour-noon,
or 10 p.m.-the sending begins.
In the transmitting clock is a tooth
ed wheel. each tooth representing a
second of time. except that the 29th,
55th, 56th, 57th and 59th seconds are
omitted. These teeth break the circuit
and cause the telegraph instruments to
tap, each tap marking a pulsation OF
the clock.
On a shelf beside the clock stand the
telegraph instruments, connected with
the several time services, including
that to Arlington.
At five minutes before the hour the
officer in charge turns L switch and
click" go the saunders. "Click, click,
click" they sound loud in the other
wise silent room. The pauses for the
absent seconds on the wheel give en-
phasis to the remaining ones. At So
minutes and 40 seconds the officer
another circuit. The result is that the
next signal is sent exactly on the
hour. 1t is about one and thirty-five
one -hundredths seconds long, while the
other signals have been only about
third of a second in direction.
The wire to Arlington from the send
ing clock runs into the sending room
at that station, and is attached to the
sending apparatus. No human hand
need touch it after the connections have
been made.
Thus, as the big clock in the time
room pulsates, these pulsations are re-
fiected in the apparatus at Arlington,
and that spits forth it's cracking
flashes: one, two, three and on; pausing
at the twenty-fifth and the other
eliminated beats. and then, in violent
crescendo, throwing forth that last,
long dash that marks the hour.
IT'S noon at Washington says the
wireless operator. his receiver clamped
to his head, as his ship rolls lazily over
the tropic seas.
Its noon at Washington" says his
brother of the sparks, shivering in his
tiny cabin, as his ice-coated ship creepS
through the fogs and lodges icebergs
off the Newfoundland coast
Its noon at Washington, says the
uniformed petty officer. grim eyed and
eager to catch every passing hertzian
wave, as the British cruiser, whose air
scout he is pursues relentlessiy the
elusive German.
All up and down and across the coun-