The Louisiana Democrat. [volume] (Alexandria, La.) 1845-1918, 1886-08-18
THE SUMS DISTANCE.
treat difference in the Calculations
Various Astronomers.


Various Astronomers.
The Grand views of magnitudes which
arise in connection with the consldera-
ton of the physical condition OF tho
SIM are. rs a matter Of course, all de-
pendent upon the measures that have
been made of it's distance. Because the
solar sphere has the apparent size OF a
one foot ball held 10S feet away, Unjust
therefore be about 100000 miles across
if it be 1903 times 100000 or 93,00O,0oo
miles away; that is in. familiar FORM
the rationale of the process by when
the idea of its magnitude has been ac-
CURED Miss Clerke relates very fully
and charmingly the history of the labors
which have been devoted by scientific
men to attain exact accuracy in this
! fundamental particular. So much the
greater pains have been taken IN the
! matter because the distance of the sun
/ is unavoidably the unit OF the measure
to be employed in making all further
| Investigations as to the profundltv, OF
space. The semidiameter of the earth 8
sphere is necessarily the fundamental
unit in astronomical seryeys; and any
error in it's determination is multiplied
in an infnity of ways in all further con-
sheraton of the planetary and stellar
distances. But the measure which has
to be accompl shed in coming to the
solution of this problem in the most
direct way is about the same tn ng as
taking the apparent size OF ahalf penny
when held 1000 feet from the eye.
This is the amount which is known as
the horizontal parallax of the sun, that
is, the difference Of the position which
! the sun holds in the vast field of space
among the stars according as it is
viewed from one or the other extremity
of the half d anleter of the earth. The
lransits of Venus have been employed
rs indirect means OF getting ut this
measure through the intervening stages
of mathematical calculations, since the
first introduction of the method by
Horrocks in 1851. During the last
two transits of Venus-those, namel y,
which occurred in 1874 and 1SS2-the
most strenuous efforts by the astrono'
mers OF all civilized nations were te
Get as exact measure as was possible
In 1874 eighty distinct stations, seat
tered over the most suitable portions
of the earth, were established at an eX'
penditure of nearly quarter of q mil
, ion of money. But tho result is tina
this method, so long cherished as tht
| fayorite of astronomers, is now fount
! to have failed them. 1t is universall.
$ admitted by all that the sun is consider
y ably nearer to the earth than it wa!
conceived to be few yearssince. But
i 50 far rs transit observations are con
i cerned, Mr.. Stone gives 92,566, 0o
& miles as the corrected distance dcrive'
n from the observations of 1874. NJ. Fay
q gives SO, $50, 900 miles; Prof. Youn!
i 92,Se5,O00 and DR.. Ball 93,o00,0 600
. Doctors, therefore. disagree in this mat
i ter very materially. From the transi
q observations of 1882 the probable erro
= was held by Prof. Houzeau, the lat
a Director of the Brussels observatory
' who devoted great LABOR and care to til
) reduction and comparison of the ca
o culations, to amount to 900, GOO eithe
; way. or TO total uncertainty OF 800
q 600 miles. BY common consent
'. the best authorities the possible error ]
n the measure of the suns distance b
o this method of observing is held to
q not less certainly than l 100000 miles
IS -Edinburyh Rcview.