Iron County register. [volume] (Ironton, Iron County, Mo.) 1867-1965, 1886-08-05
THE SUMS DISTANCE.
Great Difference in the Calculations
Various Astronomers.

Great Difference in the Calculations o
Various Astronomers.
The grand views of magnitudes which
arise in connection with the considers
ton of the physical condition of the
sun are, as matter of course, all de-
pendent upon the measures that have
been made of its distance. Because the
solar sphere has the apparent size of a
one foot ball held 10S feet away, it must
therefore be about $780, miles across
if it be 1OS times $4,000 or $4,000, 900
miles away; that is in. a familiar form,
the rationale of the process by which
the idea of its magnitude has been ac-
guired. 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 profundity OF
space. The semidiameter of the earth 8
sphere is necessarily the fundamental
unit in astronomical serveys; and any
error in its determination is multiplied
in an infinity of ways in all further con-
sideration of the planetary and stellar
distances. But the measure which has
to be accomplished in coming to the
solution of this problem in the most
direct way is about the same thing as
taking the apparent size of half 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
among the stars according as it is
viewed from one or the other extremity
of the half diameter of the earth. The
transits of Venus have been employed
as indirect means of getting at 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. namely,
which occurred in 1874 and 1SS2-the
mers of all civilized nations were to
get as exact measure as was possible.
In 1874 eighty distinct stations, scat
tered over the most suitable portions
of the earth, were established at an eY-
penditure of nearly quarter of a mil
lion of money. But the result is that
this method, so long cherished as the
favorite of astronomers, is now found
to have failed them. 1t is universally
admitted by all that the sun is consider
ably nearer to the earth than it was
conceived to be . few years since. But,
so far rs transit observations are con-
cerned, Mr.. Stone gives 1856, 900
miles as the corrected distance derived
from the observations of 1874. Nj. Faye
gives %, 800, 900 miles; Prof. Young
90, 1855, 900 and DR.. Ball 93,000,000.
Doctors, therefore. disagree in this mat
ter very materially. From the transit
observations of 1882 the probable error
was held by Prof. Houzeau, the late
Director of the Brussels observatory,
who devoted great LABOR and care to the
reduction and comparison of the cal
culations, to amount to 900, 900 either
way, or to total uncertainty of $780,
600 miles. By a common consent of
the best authorities the possible error in
the measure of the suns distance by
this meth cd of observing is held to be
not less certainly than l 800, 900 miles.
-Edinburgh ReUieW.