The Bossier banner. [volume] (Bellevue, Bossier Parish, La.) 1859-1952, 1882-02-16
The Coming Transit Of Venus.

The second one of the pair of transits
of Venus across the face of the sun which
occur in the present century, is on the
programme for next December. On the
9th of that month the phenomenon will
begin at about 8h. Ism. a. m. and end
at about 2h. Pom. p. M, Chicago time.
The transit will, therefore, be visible
through its entirety from this city, wind
and weather permitting. The next sue
ceeding transit of Venus, visible from
any part of the earth's surface. will not
occur till June in the year 20o4, or 1921
years hence.
1t is well-known that the last three of
the four transits, which are all that are
known to have been observed since the
creation" have been regarded as very
valuable for the furnishing of data for
determining the distance of the earth
from the sun, which is the unit employed
in our measures of distance of planets,
comets and stars. They have furnished
us with successfully nearing the approx
imations to the truth, though some
doubts have been raised with regard to
the relative value of the results obtained
from the transit of 1874. There is, how
ever, no room for doubt that the impor-
lance of the problem warrants the en-
ployment of all the means at our COM
mand in the effort to obtain still closer
approximation to the truth than we now
possess. Apart from its merely abstract
interest as scientific question, it is in
timately bound up with the computa-
tons of the lunar motion which are so
much depended upon by those who sgo
down to the sea in ships" The science
of navigation viii never be perfected till
we know the mean distance of the earth
from the sun little more closely than
we now know it, and are thus enabled
to calculate more accurately the ever
varying pertubations in the apparent
movement Of the moon among the stars.
The problem is, in effect, to find the
difference between the apparent posi-
tons of the planet on the sun as seen at
the same instant of time at two widely
s1ndered points on the earth's surface.
The line joining those two points is the
base of monster triangle, the other
sides of which meet at the surface of
Venus, and pass beyond her to form an
other monster triangle, the base of which
is ON the sun. Then, subsequent cal
culation gives the lengths of those lines
from the earth to the sun. The diff
Guilty lies in obtaining the measures free
from error. That is practically impos-
sible; but the magnitude of the unavoid-
able error is gradually being narrowed
down by the increasing perfection of the
instruments employed and skill in using
them.
The motion of the planet with refer
ence to the earth during the coming
transit will be such as to furnish three
available base lines, all of them termi-
mating in the United States. The other
extremities lie respectively in the neigh
borhood of Madagascar and the Cape of
Good Hope, near Cape Horn, and New
Zealand to Australia The first of these
will be available for measures at the be-
ginning of the transit, the last
named for measures of the end
OF the transit; while the middle
one will furnish simultaneous measures
for the whole phenomenon. The line
from Chicago to Cape Horn is the best,
and would be the only one calling for at
tention but for the VIGOROUSLY uncer-
tain character of December weather at
L
consideration may render it advisable to
provide for observations atthe other two
southern stations-yiz.: the Cape OF
Good Hope and New Zealand, or near
those places.
OF course plenty of observations will
be made in the United States, weather
permitting, but they will be valueless
without comparison measures at the other
sextremities of the base lines referred to.
American astronomers naturally feel an
interest in the solution Of the whole prob
lem, and are already bestirring them
selves to make the necessary arrange
ments for observing in the Southern hem
isphere. tits interesting to note that
they will probably have "a monopoly
of the Photographic method. It is not
provided for in the arrangements of the
European astronomers, the results OBJ
tanned by it having been regarded as
very doubtful. But recent comparison
of the photographs taken here during the
transit of Mercury in May, 1878, shows
that with fine weather during the whole
transit the results of the Photographic
work will be much more trustworthy than
those obtained by the observation of con-
facts. There is certainly reason to ex-
pect that the experience of seven years
ago will be of great service in the work
of eleven months hence. 1t is, therefore,
highly desirable that the work should be
done, and in the best manner possible.
AS prominent American astronomer
has remarked, even if the result should
not be all that could be hoped for, the
astronomers of the next century but one
would scarcely forgive those of to-day if
the opportunity be neglected. Chicago
Tribune.
The Rise In Prices.