The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1901-03-31
PRICE FIVE CENTS.

opposite the FrOosham clock are two less
costly timepieces, which contain the mech
anism for sending out the time signals.
These timepieces cost between 500 and $500
apiece. There is. by the way, another clock
in the observatory for which Congress caid
$4,000. 1t was invented by Dr. John Locke.
Of Cincinnati. In 1Sl9, and was the first APP
paratus for transmitting time
ally. IL is running now. but it's only use Is
10 measure time. The Frodsham clock is
set for sidereal time. Between this and
standard Eastern time there is a difference
Of s minutes 1903 seconds. The other clocks,
when they are regulated by the Frodsham.
must be made TO vary just S minutes l209
seconds from it. This is accomplished by an
ingenious recording device. A cylinder
standing on an adjacent table is made TO
revolve at a fixed rate OF speed A sta
tionary pen loaded with red ink makes a
straight mark on the paper which is fast
ened around this cylinder. In each OF the
two clocks is a cogged wheel, just behind
the dial. which turns with the second hand
Each of the cogs in turn touches a brass
spring which closes the circuit OF a bat
terry. An electric impulse from this bat
terry passes through the pen, and by a
mechanical arrangement causes IL TO make
a horizontal mark on the cylinder. Thus
every second is permanently recorded. The
Frodsham clock is also in circuit with this
pen. A cup of mercury rests in the clock
1t is connected with one pole OF the battery.
The pendulum is connected with the Other.
AS the pendulum swings IL touches the
mercury IN the cup. closing the circuit and
sending an electric impulse through the
pen. This impulse also causes the pen TO he
detected and 10 leave a mark on the CYL
Under.
1t is easy enough to set either OF the
other clocks within a second Of the Frod-
sham-to set the minute hand at the eight
minute variation and the second hand
twelve seconds more. But the fraction OF
the remaining second must be measured
with great nicely. This is done by measur-
ing the space between the marks on the
cylinder with a prepared graduated scale.
which shows the difference between the
two beats to hundredths of a second. Tho
operator doing this accelerates or retards
the clock to be regulated by touching the
pendulum with his finger till the space
measured shows that the fractional differ
ence is just nine-hundredths of a second.
Then the clock is ready for the days work.
HOW THE SIGNAL WORKS.
All this takes place not too long before
the noon hour, so as to give the clock n
Htsletime to lose or gain. There is a sounder
on top of the clock. which steadily ticks of
the seconds loud enough to be heard in the
adjoining room. At three and a quarter
minutes before noon, approximately, the big
clock is switched into the telegraph cir
cult.
This cfOpa1 OlOCE hoe q +oo+1o1 xrhooI IA
rectly behind the wheel which marks the
seconds. The wheel is divided into sixty
spaces, but the tooth representing the
twenty-ninth second is missing. and so are
those representing the thirty-ffth, fifty
sixth, ffty-seventh. ffty-eighth and fifty
ninth seconds. AS this wheel r~evolves the
teeth come in contact with a spring which
is in connection with the current, closing
the circuit and causing the sounder to re-
spond. The twenty-ninth signal drops out,
and that intermission indicates the ap-
proach of the half minute. In the same
way an intermission Of five beats indicates
the approach of-the end OF the minute.
This arbitrary arrangement is designed to
warn operators all over the country when
they cut in at just what point they have
come on the circuit. Before the final sig
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This is brought about by the action of
the operator at the observatory and is not
automatic like the other intermissions. Ii
is produced by the operator moving the
switch key, which throws out of the circuit
the wheel marking the seconds and throws
into the circuit the wheel that marks the
minutes. If an operator comes in on the
circuit and the first intermission he notes is
a single second he knows that he has come
in on the half minute. If the -intermission
is five seconds, he knows he has come in
just before the minute. but not the final
minute. If he counts more than five Sec
onds. he knows that it is the final inter-
mission before the noon hour, and he acts
accordingly.
What this operator and what all oper-
ators have to do in regulating the time
ball is to turn a switch between the sound
ing Of the fortieth second and the signal
which marks the final minute. As soon
as the operator has counted more than
five seconds in the intermission he knows
that the next signal will mark the exact
hour Of noon. The time ball has been
hoisted to its position at the top of the
pole. These poles are in conspicuous
places in every large city in the United
$1,000 AIA0tl ~ 80 - ~ ~
Union Telegraph building. The ball is OF
canvas over a globular form. There is a
mechanical device by which a single i'm
pulse sent over the wire when the time
ball is ia the circuit pulls the trigger and
releases the bali so that it falls to the bot
tom Of the pole. In the intermission which
he knows precedes the final signal. the
operator throws the switch and in this
way all the time balls in the country are
brought into the circuit with the Naval
Observatory.
SIMULTANEOUS ACTION.
In the last hundredth Of the last second
of the ffty-ninth minute Of the eleventh
hour at Washington the tooth Of the min
ute wheel touches the spring which closes
the circuit and simultaneously the time
balls all over the country drop. When
1 say simultaneously. OF course. I make no
allowance for the fraction OF a second
during which the electric impulse is going
out from Washington. Such an impulse
has been sent from Washington TO San
Francisco in 15 Of a second.
The dropping OF the time ball sets the
clocks on Governors island. one OF the
military posts at New York. through the
intermediary Of the bugle call Just before
noon Of each day two enlisted men are