Vermont watchman and State journal. [volume] (Montpelier, Vt.) 1836-1883, 1882-12-06
The Transit OF Venus.

Venus holds the key TO vast treasure OF
scientific knowledge. To-day she will I'M
lock that treasure, and having for few
hours displayed it to the eager gaze of
thousands Of scientists will close the por-
tails which shield her secret, not to open
them again for one hundred twenty-five
years. For few months past Venus
has been "the bright particular star" in
the western sky. During the brilliant
autumn evenings her glttering lamp has
been hung just above the southwest
erly horizon, the admiration and wonder
of star.gazers. Setting earlier every even
ing till December 9th, she will pass to-
day in a direct liue between the earth
and the sun, and become the morning
star. This movement Of this bright men,
Der of the heavenly host is an event of the
deepest interest to the scientific world.
Millions of dollars will be spent in observ.
ing the transit by the civilized governments
of the earth and by scientific societies every
where. Full forty expeditions, with six and
eight inch equatorial telescopes, have been
sent out to observe the interesting event.
Among other points the United States will
take notice of the transit in Patagonia and
New Zealand. The object Of all these
painstaking labors is to ascertain with
greater degree of accuracy matter which
the Biographies from time immemorial have
announced as fixed fact to generations of
confiding school children-the distance of
the sun from the earth Incidentally the
question of the distance of other planets
from the earth, from the sun and from each
other, is also to be decided by the revelations
which Venus will make to-day, If provi-
dentially the skies are unclouded along the
line Of scientific observation. Astronomers
tell the non-professional reader that by OBJ.
serving the passage of the planet over the
suns disc an opportunity is afforded of OBJ
tanning " the parallactic angle of the SUM-"
that is, the angle contained between two
lines, proceeding from the center Of the sun,
one to the center of the earth, the other
tangent to it, Upon the accuracy with
which this angle is taken depends all knowl-
edge of the distance Of the sun from the
earth and from The other members Of the
solar system, as well as that of the fixed
stars, and the velocity at which light travels.
The revolution of Venus around the sun is
made in seven and one-half months. Her
revolutions are not, therefore, coincident
with those of the earth. At such times as
she comes in a direct line joining the CEN
ters of the earth and the sun, she seems to
pass over the suns disc, and this event is
the transit of Venus. A transit occurs four
times in two hundred forty-three years, at
intervals of one hundred twenty-one and
one-half years, eight years, one hundred five
and one-half years, eight years, in regular
rotary periods. The last occurred in 1874
The next after to-day, will take place in
the year 200i, and individuals who, with
smoked glass or telescope, fail to note the
event, must take their chances for witness
ing another similar occurrence during the
period of their natural lives The star will
enter the lower disc of the sun at about half
past nine . CLOCK anu Uldke us tSTtSS az
about half-past three o'clock. A close OBJ
server may possibly be able, with the aid of
piece of smoked glass, to detect the spot on
the sun which the planet will make, but as it
will somewhat resemble speck one-sixteenth
of an inch in diameter, seen at distance of
eighteen feet, the observation with the un-
assisted eye does not seem to promise very
satisfactory results to amateurs. To stu
dents with desire and capacity for invest.
cation the event affords practical and an
interesting opportunity. The observations
of 1874 are said to have been unsatisfactory,
owing to defective instruments. The nicely
of the adjustment of the astronomical in
struments required for making these OBJ
servations, in order to secure approximate
accuracy, will be appreciated when it is I'M
derstood that by difference of one-ifth of
a second in the measurement of the angle
difference in distance of two million miles
will result in the computations.