Weekly national intelligencer. [volume] (Washington [D.C.]) 1841-1869, 1848-11-11
COAST sURvEY-TELEGRAPH OPERATIONS Fol
LONGITUDE.
FROM THE CINCINNATI GAZETTE.

CINCINNATI GAZETTE.
We learn that the Cincinnati Observatory is in
pee Teleg- connexion with that Of the Central High
School Of Philadelphia, and that the Directors Of these esta
bishmens in connection with Professor A. ID. Bache the
Superintendent and other officers of the United States Coast
Survey are engaged in making series oil observations Tor the
purpose Of determining their relative longtudes from Green
WITCH. The few supplementary instruments for this purpose
that needed at The two places have been supplied by the
Coast Survey. The extension Of the line at this end
pass through the Observatory is the voluntary contribution Of
Mr.. ORcy The details of the work entrusted to Mr.
Sears e. Walker of the Assistants Of the Survey The
general arrangements behalf Of the two Telegraph Com
panes made by James ID. Reid, Esq, Superintendent
fhe local arrangements Cincinnati and Philadelphia
made Messs Sager Lindsay the chief operators OF these
stations.
The law Of Congress under which the Coast Survey
present organized fods the erection and outfit Of National
Observatory But legislation cannot alter or diminish the
demands Of science The Coast Survey expected TO fur
nsh maps and charts Of coast and every knows that
map chart without the Longitude OF the merldans would
be Ike OF those empty crusts for pie bought OF the con-
feconers which quite insPd till they properly filled
The Coast Survey icing thus forbidden TO build obsr
vao proper does the best thing, and engages the
ssance Of the local observatoes throughout the country
Already series Of observations made for this purpose at
Cambridge, Nantucket Philadelphia, and Charleston the
Atlantic and recently they have been commenced at Gu
cnnsti.
The mystery Of The Telegraph operation for longitude is
easily explained The Telegraph line sends the Philadelphia
clock beats to Cincinnati and receives hoC Of the latter in
OllerenCc'
places found out by double process. The two differences
should be the same, both from Eastern and Western clock
signals and such we learn practically the within few
hcndrcdths OF second
The astronomers by their observations Of the ansis Of
the stars determine the respective corrections Of their clocks
in order TO make these transmitted clock beats correspond with
the true time Of the heavens The corrected difference Of
clocks is the true difference Of longude--one hour being M
teen degrees Of longitude. This hour is the time in
which the earth eyolves eastward fifteen degrees its axis
and consequently il is the time in which tie Cincinnati OF
servstoy viii to be under q star which is now
fifteen degrees to the eastward Of our meridian.
Take for instance Philadelphia and Cincinnati which
about thry-seven minutes and twenty seconds apart,
less When The Philadelphia transit Istrumc nj is under
star Professor Kendall strikes his telegraph signal key
and Prof MITCHELL hearing Professor Kendas DOT in lis
own transit room, marks the time his clock. He also
marks the time the clock when the Cincinnati tran
sit instrument has wheeled ard through some thirty
seven minutes and twenty seconds OF time fifteen times
much space in circular The interval elapsed after
correcting for the small gain less Of The clocks true
sdefeal time, is the actual difference Of longitude.
SO much for the practical operation. Let now consider
the bearing Of the coast survey, maps and charts
The Telegraph line refers all the observates Just emu.
oerated to the cardinal point Of these maps, the City
Hall, New York Then every as'ror omca observation made
at these stations fo measuring longitude from Europe bears
di,scy upon this cardinal point
When consider that within few years The received re
stve ongujes Of the ancient obsetyaories in the
world those Of Greenwich and Paris after two centuries of
L
to wonder that the relative position Of New York and
Greenwich, whose Oldest observations for relative longitude
dated from the last transit Of Venus less than century ago.
is still incomplete.
The united efforts Of all the American local oseryaories
referred they by the Telegraph cardinal poin
at New York, enlisted in the aid Of the survey mus
tend by slow and steps towards perfect result II il
understood that already the efforts Of the Superintendent O
the Coast Survey have reached that point beyond which fur
Their progress requires revision OF the lunar tables peec
they may be supposed to be- by the united excons o CT
viIized nations since The revival OF letters.
Morse's Electromagnetic Telegraph Is indeed wonder
wonders We know from every days experience that il an
initiates time and space for the present We here see it, il
its practical effect science, making up for The Deficiencies
the past
The American Coast Survey enjoys advantages from III
Of the Telegraph or longitudcs before thought o.
similar national works. Hitherto the utmost eff r Of scode
have been directed TO The measure oT the shape Of III
earths meridian. II has been reserved Tor Dr. Bache to ay
to the world the first example Of the actual measurement
the dimensions Of one Of its payaek. The shape and d
Of the parallels have hem heretofore inferred geo
nercally from those Of tae meridian The inference is pro
baby correct within very small limits Of local
but is thing TO believe truth from theoretical con
alterations and another TO know from actual measurement,
i w.