The Clarksburg telegram. [volume] (Clarksburg, W. Va.) 1874-1926, 1897-02-26
GRBRHWIcH's GREAT CLOCK.

GREENWICH'S GREAT CLOCK.
! Tbs Constan. Care l,voIv,d 1, OBJ
tanning the Correct Tine.
About four miles from London, in
the County OF Kent, is tho parlia-
mentary borough Of Greenwich.
The census folk give it population
Of about l70, 900, but it has none OF
the bustling activity ofan American
city Of the same size. Yet it has its
share OF fame, but not as great q
portion as it should have, consider
ing that it enters into the minute
affairs OF every man, woman and
child in the civilized world. This is
q pretty broad statement, but it is
the truth, as will speedily be shown.
Ask any resident OF Greenwich to
point out the most prominent fca-
ture Of the town, and it il ten to one
that hr will indicate the historic
Greenwich hospital. Ask him about
the second most important feature,
and. If he be particularly shrewd, he
may say the ROYAL observatory.
Locally the hospital is thing of
tremendous Importance, while the
observatory is seldom thought Of.
While much time is given to the
study Of the moon and other planets,
the main business OF the observa-
tory is TO secure the correct time.
To detail all OF the labors regarding
the latter would be an endless task,
and n dry one to the reader, so mere
" an outline will be given. The
mean time standard clock, which
gives the time Of day to the world,
is connected by electric action with
the mean solar clock, and is further
kept correct by calculation and COM
parison with the standard 81 ereal
clock, whose error is determined by
observations OF the stars. The side
real clock is considered the most
wonderful instrument in the obser-
vatory This marvellous instrument
is in an underground room, called
the magnetic basement, where it
stands like sentinel, with its back
against the wall, ticking its seconds
as prescribed by the clock stars. !"
This reference to the clock stars
fixed stars, slightly over 200 in
number, which are used for deter
mining sidereal time-brings US to
the transit circle, the most impor-
tant instrument in the observatory,
and one of the most interesting. 1t
consists Of a large telescope, the out
side of which is not unlike great
cannon US it is of solid iron. This
instrument is supported by trun-
Mons, which allow the telescope to
be elevated or depressed, to point
north or south, and, in fact, to make
q complete revolution, but never to
diverge from the north and south
line. The magnifying power of this
instrument is not very great, but its
field of view is large, so that it adj
mits plenty OF light, for it is not in
tended as a searcher after or for
gazing at celestial objects, but for
noting the exact time at which stars
and planets pass south and north of
Greenwich.
Upon looking through this tele-
scope the Observers eye is first ar
rested by q vertical row Of what
seem to be iron bars, placed ut
equal distance from each other.
They are, however, neither more
nor less than spiders webs-the
center one, passing through the
focus of the object glass, being the
meridian line. BY observing the
time at which the "clock stars" pass
over these web lines, or wires" as
they are called, is sidereal time
regulated. The adjustment OF the
instrument has to be extremely ex-
act in order to obviate error. The
slightest thing will put it out-even
so small matter as too much sun
shine. On one occasion the correc-
ton for o level error in the instru-
ment having become inconveniently
large, owing apparently to sub
sidence of the eastern support, about
q ton weight of stones was placed on
the western pier.
But this having no effect, the
stones were removed and sheet of
very thin paper was placed under
the support on the eastern side, by
which means the error was correct
ed. This will give some idea of the
delicacy of adjustment necessary for
the perfect working of this ponder
Gus instrument.