The Kenosha telegraph. [volume] (Kenosha, Wis.) 1860-1888, 1870-02-10

surface, twice tAe'size he does to us,and she
receives twice the amount Of light and
heat. Her motion in her orbit is much
more rapid than that of the earth, and
her orbit much less elliptical in form.
Her axis is 80 inclined to the plane of her
orbit that she has no lees than eight sea-
sons in her short year
The great point Of interest connected
with this planet, eentTcs On her approach
ing sraasits. If che plane Of the orbit OF
Venus conceded with that of the earth,
We Should, have tFaasits ct every Inferior
conjuAction, bat such is its Inclination
only at long intervals The last one took
place in 1852. the next ones will take
place in 1874, and 1854, after which more
than Q century will elapss before the re-
carrance OF another ftnighs be thcag hi
that little black spot, passing In q
straight line ever the suns disc Is Of no
importance in the history Of science, but
pAysieists and astr~asnors are looking
with intense and absorbed interest for the
occurrence Of the next transit, for the o.
luton Of the important question Of the
suns distance will be written on It's
records. The English astronomer Royal,
calls this noblest problem in astrono-
my; and without being very scientific, we
think we can give an Ineligible idea OF
the process. In order to fad the distance
Of an object frorz the earth, we mast have
\ a base line, and mast observe tho angle
made by the ends of the base line and the
distant object. The single conditi, IN
necessary, is, that the base line shall be
of applicable length This mode OF
measurement lie easily applied to the moon,
but with the sun it is not available Two
observers placed on the equator, one hun-
bred and eighty degrees apart, would give
the largest diameter for base line, but
this distance of nearly eight thousand
miles, compared with the suns distance,
becomes inappreciable, ana this method
Of measureracrt is useless In 1883 Mr.
Gregory suggested flank attack on the
suns distance, rendered possible by the
transit Of Venus over his disc. This
method is founded ON one of Kepler's laws
by which the relative distances of the
planets were determined long before their
absolute distances were ascertained. The
thing to be done is to measure the
distance Of the nearest planet from us, and
then something like rule of proportion
in arithmetic gives us the suns distance.
Venus comes near enough at her shortest
distance TO allow us to apply the base line
system, but, unfortunately, when she
comes between US and the sun, her dark
side is turned toward us, and she 10 invis-
IDLE. But this is not always the case, for
at long intervals she passes like black
dot, over his face. This event we call a
transit, and thus we see its great impor-
lance. Trl9Y
1 Let us now regard the sun as q screen
on which the planet is visible. An OBJ
server at the center of the earth would
lseesthe planet travelling in a straight line
1pver some part Of the disc. An observer
TIT the North Pole would see the planets
path projected lower down on the sun
and an observer at the South Pole would
see the path projected higher. Therefore,
as seen frem the North and South Poles,
the path of the planet would be separated
by an interval The great difficulty of
Iobtaining the amount Of separation Of the
apparent paths of the planet over the sun
lis caused by the impossibility of taking
simultaneous exhibitions; and the fact
that the earth is moving at the same
time. The matter is still further com
plicated by the different distances of the
earth and sun from Venus. In order to
make this interval between the two OBJ
servations the longest possible stations
at great distances from each other must
be chosen. Hence for the trancit of 1869
observations were made at the Sandwich
Islands, Lapland, the South Seas, &c.
In order to give an idea of the extra
Aok - I'd 10 A.
next transit, we will give the results of
the two last in regard to the suns distance.
In Fergusons Astronomy, written about
the middle of the last century, the earth's
distance from the SUMS given at eighty
two million miles. The transit of 1868
gave result of ninety -fye million miles.
The same result was obtained by the
transit of 1859 We are not now depend
ent alone upon the transits of Venus.
The base line system has been applied to
Mars, and even the velocitylof light has
been made to bear on the problem The
result of modern investigation shows an
error of four million miles This might
appear to be a great fault in astronomical
calculation, but even this error in the
suns angular diameter, if it be an error,
is no greater than the breadth of human
hair seen at distance of one hundred
and twenty-five feet. Moreover, Mr.
Stone, of the Greenwich Observatory,
has discovered mistake in the calcula-
tions of the transit Of 1869 which brings
the suns distance down to ninety, one
million miles. For his research a gold
medal has been awarded to him by the
Royal Geographical Society.
The next transit will, therefore, be an
ticipated and observed in every Inhabited
quarter of the globe, with an intensity of
interest which no natural phenomenon
has ever excited. Distant stations have
already been chosen the most accurate