Richmond dispatch. [volume] (Richmond, Va.) 1884-1903, 1888-08-08

corrccts the biz frodsham clock winch
I stands IN one corner Of the signal-room.
/ This clock is fastened TO pedestal
Of granite quite free from con
tact with the floor or any other
part OF the building. Nothing
/ but An earthquake or some other
extraordinary CONFUSION OF nature can
shake it OF interfere i'll any way with ITS
steady marking of the minutes and the
/ seconds. This clock keeps the local
| time or the time Of the meridian passing
| through the dome of the observatory.
| 1t is always right within i've hundrcdths
Of u second. its variation is amazingly
small Between this clock and the
clock which keeps standard eastern tune
/ there should be minutes and lZ'0J
seconds difference.
TIE ACTUAL OPERATION.
10 the ordinary mind the problem OF
comparing two clocks with the idea OF
measuring the difference between them
10 hundrcdtha OF seconds seems stupcn-
dous. The actual plan OF operations is
simple enough. IN the big Frodsham
clock is a little cup Of mercury. Over
TINS cup of mercury swings o bit OF steel
attached to the pendulum. The mercury
is connected with one pole OF % battery,
the piece OF steel with the other Nnen
the twO are brought IN contact the CIR
cunt is closed. On the other side Of the
room stand two plain clocks. about
which there IS nothing 10 indicate "a
value Of 800 or $SOo These clocks
were purchased at the time Of the tran
sit Of Venus In each of them is cog
ged wheel just behind the dial which
turns with the second hand. As each OF
the cops passes q point IN ITS path It
touches brass spring which closes an
electric circuit. With each second,
therefore there is en- electric impulse
sent forth. On a table between the
l'rodsham and the other clock is o chr0-
uCcraph. il consists Of a metal cylinder
winch is made to revoiya by O hidden
spring at certain uniform rate the
rate being timed, each revolution OF
the cylinder covers a certain time
space and the circumference of the
cylinder can he divided into fractions
of that time OF intomluEtes AMI fractions
of minutes. The cylinder is covered
with paper. On the paper rests apen-
point. As the cylinder reyoNcs the pen
traces on the paper red line. An eiec-
tric attachment 10 the pen causes il 20 ice
DETECTED from it, position at ihe passage
of an electric Impulse.
The two clOcks-the Frodsham and
the transit clock are put iu circuit with
the pen on the chronograph. At each
second registered 10y the Ffodsham the
pen IS DETECTED, making q marked point
at right angles with the straight Inc 1t
was drawing along the paper on the 'cy-
Under. At each second beat Of
the transit clock also the pen Is de
hectei. The distance between these de-
Elections being measured with pre-
pared graduated scale it can be deter
mined within few huudredths Of q
second what the difference between the
two clocks is. II II is desired 10 retard
the movement of the transit clock in
order to make the difference between
the clocks greater, the operator with his
lead-pencil checks hependulum slightly.
II he desires to lessen thc difference be-
tween the heating OF the tgo clocks he
in the same manner accelcrates slightly
the motion Of the pendulum. The diff
ference Is at once marked, even 10 the
ear. for ON top of each clock Is an cleo
trc sounicr like that attached 10 uuy
telegraph instrument
THE ELErIMCAL CURRENTS,
The transit clock having been cor
rected at three and onefourth minutes be-
fore noon the clock is switched into the
telegraph circuits leading from the OBJ
selvatory to the Offices Of tie Western
Union Telegraph Company, the signal
service, aud the iiFe-alarm. The little
wheel which controls the electric I'M
pulse has tie cog representing the
twenty-ninth second and the cogs le-
presenting the last five seconds
Of each minute cut ont. In tins
way any operator who cuts INTO the
signal crcut at any time after tie
signalling has begun is able 10y the
omission Of one Of the regular beats 40
distinguish the next as marking the hall
minute, and by the omission Of hyo to
know that the n vt beat viii represent
the close al the full minute. Automaji-
cally tae clock sends as puisatious over
thousands Of miles OF Wire thus for three
minutes. There are fifteen seconds 20
be measured of before TIE noon EOur
The operator steps forward aud place,
his hand upon sRIteh-ACE. one, two,
three, four. five, the swit,h is thrown.
1t throws out of play the cog-vheel
which marked of the seconds and throws
into control of the circuit "A cog-wheel
which marks Off the minutes. For ten
seconds then. or until the minute has tx
PRED, the circuit will remain unbrokon.
there will he no electric Impulse sent
ont. The operators listening for tie
time have counted from the last break ia
the beating twenty distinct impulses.
When the beating stops on Che twentieth
they know that the next impulse VII
mark the close of the hity-nlnth min
ute of the eleventh hour. In response to
ibis signal the operator in charge Of the
tiine-ball on the Western Union building
in New York throws a switch which
brings into circuit the wire leaiing 10 the
machinery which controls the ball. The
adjustment OF that machinery Is such
that single impulse will release the
ball. At Woods Holl, Mass, at New
port. II. l., at New Orleans, Savannah,
Baltimore, Philadelphia, Hampton
Roads, and Washington the operators in
charge Of the time balls switch them into
the circuit
CLOSING THE CIRCUITS.
For this brief ten seconds the Naval
Observatory has control OF the Western
Union wires and they arc absolutely idle.
The minute wheel turns on It's pinions.
AS the last hundredth OF the last second
OF the fifty -ninth minute Of the eleventh
hour expires the wheels single tooth
comes in contact with the spring. in
the instant OF that contact the circuit IS
closed with the swiftness of the light
ming bottled up 10 do mems bidding and
tho impulse beats over the wire. In that
Instant responsive 10 ii the tine-balis
drop, the bells in hundreds OF spots far
aud near ring out, and hundreds Of
clocks in this city and hundreds more at
distant points change their indication