The Anderson intelligencer. [volume] (Anderson Court House, S.C.) 1860-1914, 1874-07-23
The Transit of Venus.

line current year Will become Il uOGlUle OHC
in the annals of science, because Of the phenom-
enon occurring on the 9th of December, which
is known to astronomers as the transit OF Venus:
More than one hundred years have elapsed
since the last occasion Of this transit Another
will transpire in 1882, for according to the re-
spective motions of Venus and the earth these
transits, when they do happen, occur in cou-
pies and at short intervals, but there will then
be no other transit until the year 20O4.
The phenomenon alluded to is the passage OF
the planet Venus between the earth and the
sun, in such position with regard to the
earth's orbit, that Venus is seen to move like
round black spot over the suns surface. The
Importance of this phenomenon in scientific
point of view, may be judged from the fact that
it affords astronomers the best means of meas
uring the distance of the heavenly bodies, and
of obtaining their weights and dimensions.
The observations of 1869 have formed the
basis of all the accepted facts of modern as
tronomy, so far as the computation of distance,
etc., is concerned. Of these data it is that we
have all learned from our early years that the
sun is distant from the earth more than ninety
million of miles, that Mercury, the planet near
est to the sun, is 38,SOO,000 miles away from
it that the distance of Venus from the sun is
more than 6S,O00,000 of miles and so on.
But it is singular fact, that Notwithstanding
the care with which the observations were made
in 1859, and the frequency with which these
observations and the calculations based upon
them passed under the examination OF the most
distinguished astronomers, it was discovered
only few years back, that certain errors had
crept into the reckonings, by which the suns
distance was overestimated by about tour mil
lion of miles. This error has necessarily affect
Il Ill IL, ot1,o ,totio hot
a century, as one writer has put the matter, the
distance ofall the heavenly bodies was over-rated
by over four per cent and their weights by
more than twelve per cent, and these inaccu-
racies will be found in the best authorities on
the subject, except those that have passed
through recent additions.
The discovery of such errors, under the Sc
we're processes by which modern research is
conducted, has led to increased anxiety on the
part of the scientific world to secure the most
perfect accuracy in every detail connected with
the next transit. It will therefore be watched
with the greatest care by astronomers all over
the world, their observations will afterwards be
compared, and the results finally given to the
world, will, it is hoped satisfactorily settle the
questions involved. The recurrence Of tran
sit in 1882 will afford an opportunity of devo-
ting renewed attention to any point or points
that may be left in doubt by the transit of 1874;
and in the present state of scientific knowledge,
we may expect much nearer approach to pos
tive accuracy than was possible in the last
century.
The points of chief Importance in making
observations of transits, are the moments of in
gress and egress ofthe planct-that is, when its
black shadow first appears in contact with the
lumnary; again when the whole of the dark
surface is fully projected, and lastly, when the
planet reaches the suns opposite margin, begins
to disappear, and finally vanishes. All these
points noted and timed by different observers
all over the globe as far as practicable, and at
terwards compared one with the other give the
data for perfect record Of the transit, and for
theimportant results already mentioned.
The transit next December will be invisible
in those parts of the earth where its phenomena
could be most easily observed. J. will however,
be visible in Northern India, China, Japan, and
other points in Asia, Australia and New
Zealand, the Mauritius, and other out-of-thc-
way places, and to all these points expeditions
will be sent by the Governments of the United
States, Great Britain, and other nations. The
reason of this great variety of stations, apart
from the fundamental necessity that observa-
tions should be taken at parts of the earth as
widely different as possible, is, that the state
of the weather and condition of the atmosphere
at some of the places may not allow of q clear
view of the passage of the planet over the suns
disc; and therefore, if observation should alto
gether fail at some points, it will undoubtedly
be successful at others.
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