The New York herald., 1874-12-07

at washington, while the observers see
that It is midnight with them. then !,
time different from that OF Washington
Every hour OF difference in the time shows re-
movai Of fifteen degrees or one twenty.fourtn part
OF a circle round the earth. from Washington; I;
hence the observers would be twelve times nteen
degrees RON our capital But as the very oes.
Chronometers fail to keep exact time otner means
are resorted to. The moon, during her circuit
round the earth, passes between US and certain
stars. The moment at which sne passes between
any star and Washington Is known from prevlo
ejaculation. II. then, 1t be found at q tain
station tnat the moon passes over the same & star
eight hours earlier than at washington the o0ser.
vers can estimate their Longitude rs before.
Eclipses OF Jupter's moons occur with marvellous
become visible on an island and comparing
this time with the hour At wnlcn the almanac
gtude can be determined as pe ore Best OF all
systems, perhaps, is the electric telegraph. II. Tor
instance, when It IS noon at HOBART Iown the
wires nash from Pekln the intelligence tnat 1t lS
two hours three minutes and twenty -eQnt seconds
before noon there, It becomes evident that Hobart
Town Is thirty degrees and nve-six hs east OF
Pekin. In these ways the precise location OF
every position on the earths surface can be deter.
mned. Tne amount OF error made by the oocks
can be rectifed by observing the time when
elapses from tDe instant At which star passes
the meridian on one night 10 similar moment on
feet time 1t Will indicate lapse OF twenty-tnree
hours ffty-slx minutes and our seconds II IL De
SLOW Iast, compared with the stars, Its error
can be cOmputed and allowance made therefor.
THE PHOTOGRAPHIC ARRANGEMENTS.
At each Of the American stations upwards OF 200
white o. an egg III water and little nitric acid.
Coodlon Is then poured over them, and they are
Venus. Tle Image 81 the small strip OF the sun IN
the neighDorh00d OF the contact Is Admitted
through slit and strikes the glass One OF the
plates IS introduced the moment Venus touches
the sun, ana u perfect representation OF the ap-
pearancc rs imprinted on the plate. This image ls
pas ed to an attendant who lastens the impress
SION as IN ordinary photography and In the mean
time another plate is introduced into the camera
SO on. In this way about 200 negatives
81 the an during o s scb t and s
be copied. The two methods Of Haley and Delisle
respectively, iull explanation 0l the nature oi
winch has already been made in the HERALD Will
be used according to the taste OF the observers
and their positions on the globe. Halley's method
sible; in Delisle's the locations lie and west
Tue committee appointed 0y our own government
Tlll employ the system Of HALEY, while tnat Of
Delisle will be used by Sir George Airy and the
Russian observers. The French and the Germans
wn take advantage OF botn having selected sta
tOns at four distant corners OF the visible portion
THE EVENING OF DECEMBER 8,
when It VIII be thlrty.nve minutes past eight
the 9th at all the American stations. During the
lew decisive minutes after that time the Whole
pointing their telescopes toward the sun and
praying iervently that no clouds may intervene.
ton ali the exertions sand and time and money spent
on that particular locality will nave gone Tor
naugnt. Gold medals. honors and greatness Of
name await the fortunate solder VINO will best
perform the task. ls It any wonder that
they should betray anxiety to witness the
grand event under favorable auspices Theirs
Will be no transit0ry merit. for the history OF their
glorious works will be inscribed forever upon nts-
t0ry's most luminous pages, ana Will go down
from age to age as an impertsnahle monument OF
the genius, the energy and the triumphs OF science
In the nineteenth century. While wearied mortals
VIII be wrapped in reDose over the extent oil our
own land the apostles OF science Will be absorbed in
scientific reverles beneath the sun OF other cmes,
and Winning wreatns of lame more durable than
the laurel or the imperial crown. 1t Is not I'm
Moderate to hope that America Will not be the
east among the nations In this heroic and peaceful
con test Ior honor ana iame.