Clarksville weekly chronicle. (Clarksville, Tenn.) 1873-1890, 1874-12-12
THE TRANSIT OF VENUS.

A little before nine clock thiseven-
ing OF our time. the planet Venus will
first be seen entering upon the face of
the sun on the side of the earth on
which it is then day. but only in the
southern hemisphere. The planet
being some twenty eight million miles
from the earth. and sixty-fiye from the
sun. it will be invisible to the unassist-
ed eye, but seen by the aid of tele-
scopes and other appliances. as small,
black, circular spot moving acro,s the
upper part of the solar disc, during
ONE four and half hours. Our
American astronomers have selected
eight different and distant places for
observation and if no clouds or other
Instructions intervene, they will
doubtless give an interesting account
of their mission.
Other nations have over sixty bodies
Of scientific observers widely distribu-
ted to watch this celestial phenomenon,
and gather as many facts as possible.
That governments should take SO
much interest in an event twenty-eight
million miles distant from any human
,bode, amounting, apparently. to only
small black spot" invisible to com
mon ewes, is itself owing to the fact
that Venus makes about thirteen rev.
buttons in eight years, her transits
frequently come in pairs eight years
aplrt, though with an interval of. over
"A century from one pair to the next !;
thus the transits orcurred in Decem-
ber 1851. and 1859; in June. 1861. and
1863 a will occurin December, 1874,
and 1882. They can only occur in the
month having the longest and the
,hortest days. That of 1851, though
predicted by Kepler, was unobserved.
That of 1899 was calculated and OBJ
served by young astronomer, Jere-
miah llorrocks, who darkened his
room ami let in sunlight on a sheet of
white paper, through an aperture in
window shutter. 1t was Sunday, and
the pious astronomer watched his
paper till it was time to go to church.
This duty he would not neglect,
although another opportunity TO wit
ness the transit Of Venus, and demon
strate the wisdom of some years study
rnd labor, he knew would not be Of
fered for century. Returning from
church in the afternoon. he resumed
his observation, and thus describes
what followed: AT this time an
opening in the clouds. which rendered
the sun distinctly visible, seemed as if
Divine Providence encouraged my
aspirations. when. oh most gratifying
spectacle, the object of so many earnest
wishesl | perceived new spot of
unusual magnitude and perfectly round,
which had just entered on the left
limb of the sun"
In l76l Capt Cook made his first
voyage to Tahiti to observe the transit
of Venus. Vary a mathematical line
but hairs breadth in 1000 feet, ex-
tended from our planet TO the sun, and
it will shorten the distance to the sun
three million miles; or from % co.,
600. as our early school books have it.
to 92091, 600 miles. Astronomers are
trying to make this distance an accu-
rate and reliable yard-stick by which
to measure other celestial distances.
They want an astronomical unit, and
to-dac they hope to find its base. using
all previous knowledge and their hest
appliances for that purpose. From
Ptolemy to Kepler Astronomy made no
progress, standing still more than a
thousand years. Now it has the largest
sympathy, and is mixing substantial
advancement.-U Union and american,
Sth.