Weekly national intelligencer., 1851-11-08
,adTED erATEs COAST SURVEY.
of Esarcty for Gscertaining Latitude, Longs
tude, &c.


= -.
of Rsriey for Gscsrtaning Latitude, LOngi
tude, de-
yRA THE SAVANNAH aKruBLIcAS.
~ ,n ,,poses Of the Coast Survey, the coast Of the
Ird G divided into series Of sections each having
I an oAs extent of shore line. In each section base
na Z assured, and series Of rangles formed upon IT,
nsax along the coast in each direction from the hase
A. Of tianses in each section reaches It's exterior
mF meets similar chain coming from the base OF the
Section, and unes with it. eventually forming one un
en SERIES extending the whole length Of the Atlantic
I'D Gulf coasts Of the United States.
BY this plan Of operations which devised DC en-
carried out by the present Superintendent of the Coast Sur
vey Prof. BAcHE the work goes in every section at the
me and the period required to survey the whole coast
is reduced to that necessary for surveying any one secuon
The system and methods employed every secon
and each its boundary unes with the others, each
also proUes the Others
The fifth section includes the Atlantic coast from Cape
Fear to the st. Mays The base OF the work in this sec,
ton upon Edo island, South Carolina. It selected
and laid by your ionsDan, JAMES s. WILLIAMS, Esq
It's site is admirable one and reflects the highest credit
upon Mr.. WILLIAxss skill and good judgment in very
difficult matter. II measured by the superintendent
Prof BAcHE last year. and the process Of ansustion n
each direction from it 10 going on But In this nat and
wooded country the formation Of system OF rangles having
sides from eight to twelve miles in length Is necessarily slow
and tedious Nearly every side requires the ee use OF the
render the signals at the exsmities Of the line inter-
visible It will require several seasons work to reach Sa
vannah in the regular course Of the survey,
Al the close OF the MEASUREMENT Ot udsc
BAcHE visited Savannah and at he request Of the Chamber
Of Comm and others interested in navigation. ordered "A
separate survey of Savannah river and lis 70 Dc
made immediately, to be connected with the survey OF the
progressed South. but to be distinct and complete
in ITSELF and available for navgaors several earlier than
it would have been taken up in its regular order The
survey commenced in March, 1885, and continued until
the first Of May Of that year. i was resumed IN January
last and is still in proeress. In the course OF it the
nomcal observations have been made Of which you have
requested description. sssp4 FHp3. itsa s.
The survey Savannah river rests for the present. upon
base %sfssAea aA An 81 soss intended to the
and county bordering upon il from the bead Of Hutch
nsons Island to the These ranges furnish the
lative positions Of large number Of points, the distance
and direction Of each point of the system from every other
point This operation constitutes the tongUon and fur
survey Of the land and the photographed party
equally accurate survey the water These parties
at work.
But the ranguaion gives only the relation Of each point
to the Others To form complete chart il b necessary to
determine the absolute geographical position Of
point from whence that of all the others may be obtained by
calculation This has been the object Of the astronomical
observations completed They have been of three classes
latitude, longitude, and szimuth.
observations for latitude in the Coast Survey have for
some years past been made with instrument called the
zenith telescope The mode Of observation that first
gested by Capt ANDREW TALcor, formerly Of the U. s.
Corps Of Engineers and since pracced with many
American observers. 1t conss in observing with micro
meter the difference Of zenith distance Of stars north,
and the other south OF the zenh and making nearly Inc
angle with it. With the aid of the catalogue Of
stars by the British Association for the advancement Of sci
containing the places eight thousand stars,
such pairs may be selected for any latitude The instrument
used at this station made in Washington by Mr. WUR
DEMANS, and is the first American instrument of the kind
Mr. Wurdemann has improved very much upon his English
models and has produced the best zenith telescope in Ame
rica both in symmetry and accuracy workmanship and in
adaptation to its intended purpose series of observations
for latitude has been made with this nsumen which, when
reduced will furnish very close approximation TO the truth.
significant fact in the history Of modern progress in as
onomy, that is found necessary to increase the number OF
stars observed rather than to multiply observations upon the
pair Experience has proved that upon tie average,
the probable Of observation for latitude with
strument he that above described is about fifth great
the probable Of the places Of the stars in the
British Associations catalogue. The latter the mean
result Of observations made different observatoes in Europe
various periods in the last and present centuries But the
advance in astronomical science and in of
observation during the last fifteen years has been rapid
that determinations Of the places Of the fixed
necessary to keep with this ADVANCE and being
made the National Observatory Washington and other
observatories in this country and Europe.
The observations for difference OF longitude Of the medsns
Of Prof. LEWIS R. GIBsEss Observatory in Charleston and
the Exchange in Savannah have been of exceedingly in
teresng character Through the kindness of Mr. ALExAN
President Of the Washington and New Orleans Tee-
graph Company, have been allowed the free of the
wires between Charleston and Savannah business hours
The instruments used have been astronomical clock from
the mandatory Of the celebrated Kesses Of Aona the
Savannah saon and two transit telescopes mounted upon
s0ne-DOcKs In such manner that the telescopes the
great circles of the earth constituting the merdans Of the
observatoes Morse register and flet like that used in
the telegraph Offices in each observatory. Mr.. SAX
TOM the Coast Survey Office at Washington, has attached
to the clock apparatus Of his invention for rendering
the clock atc causing to record its time upon
the Morse fllet gavanic circuit is carried through the
cockcase close to and directly in front of the pendulum
small and delicaey poised platinum hammer, resting up
platinum bed, forms part Of this circuit. Attached 10
the rod Of the pendulum small insulated piD adjusted
that at each oscillation Of the pendulum, when is at the
up, and breaking the circuit The time occupied in open
ing and closing the circuit at each oscillation Of the pendu
lum, about fve-hundredhs o second Of time. The cir
cult leaving the cock passes through insulated wire
breakcireut key, placed at the side Of the eransnsrumen
and within reach Of the observer the telescope Thence
passes through the Morse register to the other pole Of the bat
terry The mode of operating in the telegraph offices now
well understood that general description Of the register
and fllet will sufico
made upon long strip of paper called llet. The
marks not indicated upon the et by any dscooraon
Of the paper in writing with ink but by series Of raised
lines grooves with blank spaces between When the gs
vanc circuit is compete continued groove is made upon
the paper by the action of the pen-lever When the circuit
is broken the pen lever falls from the force Of the spring be-
meath, and the paper is left blank When the clock put
into the circuit is completed for nnetyfve hunded,bs Of
second and is broken BY The pendulum for the remaining
et representing ninety fve-hundedths Of second and
blank space for the remainder The length Of the line de-
pends upon the rspidy with which the let made to deli
the paper This Is regulated by train of clock-wok
with weight attached for the moving power. The usual
length Of second Of time upon the 6let about hreequar
U uIiu
When the pendulum let's fall the tilt hammer and closes