The Marietta journal. [volume] (Marietta, Ga.) 1866-1909, 1874-08-14
The stlarietta golsrnal.
Marietta, Ca, Friday, Aug. IA, 1874
For the Journal.
THE TRANSIT OF VENUS.

While the different governments
are busy fitting out expeditions to
the most favorable points of the
globe in order to make observations
upon the coming transit of Venus
which falls upon the Sth Of Decem-
Der, and while the subject is noticed
as a topic Of general interest, still
there are comparatively few who
know anything about the. transit Of
Venus or what it promises to science.
Venus is one of the inferior plans
cts and consequently moves around
the sun in an eliptical orbit less than
that Of the earth. The path of the
earth around the sun is called the
ecliptic and the plane Of the orbit of
Venus is inclined to this 1T an angle
of about 800 degrees. We're it not
for this inclination we would have a
transit at every inferior conjunction
and would not have had to wait in
longing expectation from 1863 to
1874, period Of l05 years. Now
these two planets meet in what is
known at the line of nodes and
when the line of nodes falls at the
inferior conjunction, then we have a
transit. A transit of the same node
occurs once every 235 years and at
these are two nodes we have trans
it every 105 years and years there
after and 12l years and s years
thereafter according as it is the. as
cending or descending node. The
last transit occurred in June 1863
and the next will occur on Decem~
Der sth, 1874, and then again in
1882. Aftes this none will occur
until the year 2004.
The object aimed at in making
observations upon this transit is to
determine the correct horizontal
parallax of the sun. Observations
made in 1863 placed this at SO,
while observations of a different
character put it down at S-S4S.--
This latter is thought to be very
nearly correct and it is for this err
ror Of about one fourth of Ia second
that SO many millions Of dollars will
be spent. We have a very ill-con>
ditioned triangle in determining the
distance to the sun and as this hori-
zontal parallax is the angle at the
base, this accounts Cor its being 80
important. The entire business is
nothing more than a means of de.
termining the exact distance to the
sun.
The distance to the sun is the as
tronomers base line and hence the
need of having it correct. 1t is
with this that he triangulates space.
This being accurately known, then
he can tell us the magnitude and
masses Of all the planets, the true
dimensions Of all their orbits, their
rates of motion around the sun and
their respective distances from the
sun and from each other.
The United States alone sends
eight parties three of which go to
the northern and FIVE to the southern
hemisphere. Of those going to the
north, one goes to Wiadwotok in
Siberia, one to Nagasaki, Japan,
and the third to Pekin, China
Those going to the South will be
transported in the sloop Of war,
Suatara. She will proceed first to
Rio Janeiro, thence across to Cape
Town where she viii make her final
preparations. Then she will sail
and leave one party upon the Gro
zet's Islands, one upon Desolation
Island or Kergnelen's Land, one at
Tasmania in New Zealand, and one
upon the Chatham Islands in the
South Indian Ocean.
This may possibly give some idea
Of the national Importance attached
to this phenomena and were it to
cost the nation twice what il does,
we would say that 1t mas soortb the
money.
G.. FoREsT.