The New York herald. [volume] (New York [N.Y.]) 1840-1920, 1848-11-17

COAST SURvEY-TELEaRAPH OPERATIONS FOR
LoNGrrU We learn that the Cincinnati Obser-
that of the Central High School of Philadelphia and
that the directors of these establishments in
ton with Professor A. d. Bache, the superintendent,
and other officers Of the United States Coast Survey
engaged in making series Of observations for the
purpose Of determining their relative longitudes from
Greenwich. TIE few supplementary instruments for
this purpose that wereneeded at the two places have
supplied by the Coast Survey The extension Of the
line at this end pass through the Observatory is
the voluntary contribution of Mr.. O'Reiuy The de-
tails of the work entrusted to Mr. Sears c. Walker
fhs assistants of the The general arrange
ments behalf Of the two telegraph companies
made by James D. Reid, Esq superntendent The
local arrangements at Cincinnati and Philadelphia
are made BY Ms.srs stsger and Lindsey, the chief
der which the Coast Survey is ct present organised
forbids the erection and outfit of national observa
tory; but legislation cannot alter or diminish the de-
mands of science. The Coast Survey is expected to
furnish maps and charts of coast, and every
knows that map ., chart without the longitude Of
for pie bought of the confectionery which quite
insipid till they are properly filled The Coast Survey
d6es the next best thing and engages the assistance
Of the local observatories throughout the country
Already series Of observations are made for this
purpose at Cambridge, Nantucket Philadelphia,
and Charleston, on the Atlantic and recent.
ly they have been commenced at Cincinnati The
te
dephia clock beats to Cincinnati and receives those
Of the latter in exchange. Thus the difference Of
u
process The two differences should be the same both
from eastern and western clock signals and such
learn is practically the case, within few hu ndredths
Of second. The astronomers, by their observations
Of the transts Of the stars determine the respective
corrections Of their clocks, in order to make these
clock beats correspond with the true time
Of the heavens The corrected difference Of clocks Is
the true difference Of hour being fifteen
degrees Of longitude This hour is the time in
which the earth revolves eastward fifteen degrees
its axis and consequently 1t Is the time in which the
Cincinnati observatory will move 80 as to be under
IN
meridian. Take, for instance, Philadelphia and Gin
cinnati, which are about thirty seveu minutes and
dephia transit instrument is under star, Professor
Kendall strikes on his telegraph signal key, and Pro-
fessor MITCHELL hearing Professor Kendals dot in his
own transit room, marks the time on his clock He
also marks the time the clock when the Gin
ciunati transit instrument has wheeled eastward
through thirty minutes and twenty seconds
OF time, fifteen times much space in . circular
The interval elapsed after correcting 1t for the
small gain Joss Of the clocks on true sdereal time
is the actual difference Of longitude SO much for the
practical operation Let consider the bearing
Of It the Coast Survey maps and charts. The tee
to the cardinal pont Of these maps, viz the City
iizi New York. Then every astronomical obser-
vation made at these stations for measuring longitude
When We consider that within few years the re-
ceived relative longitudes of the two most ancient
0bservatories In the world those Of Greenwich and
changed second Of time We may cease to wonder
that the relative position of New York and Green
dated from the last transit Of Venus less than
fury ago, Is still Incomplete The united efforts Of all
the American local referred they
by the telegraph to one cardinal point at New York.
enlisted in the aid Of the coast survey must tend by
slow and sure steps towards perfect result 1t Is
understood that already the efforts Of the Superinen
dent of the coast survey have reached that point
beyond which further progress requires revision Of
the lunar tables perfect they may be supposed to
be- by the united exertions Of civilized nations since
the revival Of letters Merses Electro netic tele
graph is indeed a wonder Of wonders, We know from
every days experience that 1t annihilates time and
space for the present We here see It, In It's practical
effect science making for the deficiencies of the
pact. The American Coast Survey enjoys advantages
from the of the telegraph for longitudes not before
thought Of in similar national works Hitherto, the
utmost efforts Of geodessts have been directed to the
Of the shape of the earths meridian. 1t has
reserved for Dr. Bache to give to the world the
first example of the actual measurement of the dimen
sons Of one Of les parallels. The shape and dimen-
sons Of the parallels have been, heretofore inferred
geometricay from those Of the meridian. The infer
is probably correct within very small limits Of
local discrepancies; but it Is thing to believe
truth from theoretical considerations and another to
know 1t from actual measurement Cincinnati Ga
zette.