Weekly national intelligencer., 1851-11-08

reures npe three sends Of Time, thus enabling he
to ecogniu the INLET the beginning snd ending
Qepous and delAe IL complicated 10 Be described here
The observe could break the circuit at will BY tapping
the kew al th, ade Of the instrument The anseescopes
were each farsshed with twenty6 vertical wires in the h
Gu, Of each slsss The wires equdssn, and the mid
die wire IVES the meridian Of the place Of observation
An observation Of the transit OF star across the meridian
of either station 10 made in this wse The observer know
ing the time that the star will be on his meridian places his
telescope the proper position bring the star into the mid
die Of the field The register is then set in motion, and the
clock graduates every second upon the paper he While
the diurns motion of the earth causes the star appear TO-
rapidly the field Of vson be taps the key at his
side at the moment Is behind each OF the 20 wires Oh
his instrument Each tap breaks the circuit, and causes
blank space to appear the 6e n the manner
scrbed These s0vsgna they called are aIbtra-
ry and fall upon all OF the seconds, depending on the
instant Of occurrence Of the recorded The time
cupied by star In the zenith Of Savannah in crossing the
IS wires Of the transit instrument il minute and twenty
seconds Some minute 10 therefore sure fall upon
the record Of each aran and this may be easily
missed upon the et by its double length From the pre-
else instant Of each sarssnal may be read eff Knowing
the whole length of the line representing the second upon
the le the fractional part may be measured with scale
and divide with transparent scales made for the purpose
The Of the whole IS wires gives the time Of transit
curacy.
In the observations for difference Of longitude, when the
observatoes connected, preliminary
ton respecting the work il held very much in the manner
converse by writing Chsheston then says to Savannah
sPut the clock, when Savannah brings the clock into
the ccu and Immediately the Observers in Charleston hear
their magnet beating in unison with the beats Of the clock ID
Savannah The Charleston observer being at the east
station then selects star from list previously
agreed upon and taps bis key passes the wires Of his
instrument In the above described The record of
the observation 10 simultaneously made upon the lets at
Charleston and Savanna In about five minutes the earth
will have revolved sufcieny far eastward to bring the same
upon the meridian Of Savannah and render Wis bic in
hvy sa ns BY the wires and the record made
before. simultaneously Cor nearly 10Y Savannah and
Charleston Charleston then sends the the list
and Savannah returns it and the process kept up until
twelve fifteen stars have been exchanged 10 each
the 10 observed both saons all errors in
the tabular places Of the stars are avoided and the difference
time shown the clock Savannah between the passage
Of any star the medians of the two obervaores is
precisely the difference Of longitude sought
The degree Of accuracy atainsbe 10 this is truly
dernl Prof. GIBBEs states that the probable Of
nights work between Charleston and Washington, when
only five stars observed, was less than the five hun
dredh part of second" In this rather than fifty
have been observed each station, and still closer
poxmaion to mathematical certainty should result Gem
orally it may be stated that the difference longitude Of any
two places connected by the magnetic telegraph may be de-
erined with precision Of the order Of accuracy
that Of the latude result never obtained BY any other
means. s3 Hd asFsfels 4sAa ttgs
The centre of the Exchange sprs in Savannah of
the points Of the main chain OF anges and all the obserya
ons Of every class referred to central point The
observations aZmun made This Duld-
ing They consisted in the determination OF the angles made
by the ides of the tianges radiang from the Exchange,
with the meridian Of the place Of Observation technically CALI
ed the aznuth The mode Of observing to measure with
repeating heodoe the angle between the pole star in
part Of its orbit and small lamp placed the tgonome
metcal station at the south end Of the base line, Union
Ferry Causeway Knowing the latitude and longitude OF
Exchanges and the azmuh and distance Of other sta
ton the latitude ongude, and azimuth Of the other point
be determined by calculation. This point again affords
new data for computing the position Of the next point in the
series Of angle and the calculations carried until
they checked by arriving another astronomical station
These last ususlly intervals Of about forty miles
The discrepancies between the astronomical geodec differ
Of latitude and Longitude afford data going to show that
Of density in the strata Of the crust Of the earth ex
ercse serious influence such observations and that the
nicer and more elaborate astronomical determinations Of
graphical position may yet become in the hands Of the
geoogs to enable him discover the interior character and
structure of the earth ffs
One observation in closing this already protraced
communication Three years experience in asronomicaob-
servations in this climate enable the writer with
degree Of confidence that the general condition
atmosphere s such to be highly favorable the Of
telescopes with high powerr Astronomers experience
great difficulties from the irregularities Of temperature Of
atmosphere rendering vision with telescopes Of high magn
lying powers very ndsnct On clear cold nights, when
the stars appear to twinkle most beautifully and to shine the
brightest to the unasaed eye, when "the chill spar
kle the astronomer nothing Every object appears
confused and irregular in his telescope His richest harvest
frequently when sish. haze the heavenly
dies with fmy ye through which the smallest objects can
be distinctly seen. In this climate the number Of still nights
j. when the outlines Of the heavenly bodies appear cer
and distinct greatly ounuber those in northern la
tudes where our observaories mostly situated May it
not be hoped that the time will arrive when the beraly and
public spirit Of all interested in science for its sake and
IN astronomy tending improve the safety Of navigation
will combine to observatory furnished with instru
mens OF character to enable the avail himself
OF the favorable condition Of the atmosphere hero existing
improve and perfect this attractive and useful Of all
branches of scientific inquiry G. o. B.
SPAIN AND CUBA.
We learn Madrid uaners fhat M IAannnr Late Snan.