The Portland daily press., 1900-06-29

An accomplished ASTRONOMER mas Just
made n discovery In the heavens which
merits our Close attention, for 10 ampli-
flies human knowledge OF the condition of
an interesting neighboring world. The
neighboring world Is the beautiful planet
Venus, and that the discovery should
have been made lust now will occasion no
surprise to anyone who has watched the
brilliant orb which has for weeks been
adjoining the evening sky.
Venus possesses q special and particular
interest from the circumstances that 10 IL
a globe which In many respects has q
startling resemblance to the earth. To
begin with, the beautiful evening star is
almost exactly the same size rs the globe.
The number of miles traversed In max
ing a voyage around the equator of the
earth would be almost identical with the
nu mber of miles which would make an
equatorial girdle for Venus. Nor does
the reese mblance between the earth and
the planet consist merely In their equal
size. The two globes have practically the
same weight.
II there were pair Of weighing scales
so mighty that Venus could be put into
o ne pan and the earth into the other no
great difference would be perceived be-
tween the weights OF the two celestial
orbs. Two billiard balls (which had no
greater proportional difference In size and
weight than the earth and Venus would
be practically indistinguishable. The
resemblance between these twin planets
has, however, been carried much further
by the interesting discovery which has
just been announced to astronomers.
To a planet which may be the abode
OF life one OF the most important condt-
lions will be the succession of day and
night. Whenever the question as to the
res emblance of another world TO the
- fIEAfs
how far the Inhabitants of such world.
II inhabitants there be, resemble the
people OF the earth in the enjoyment OF the
alterations of day when the sun Is in
the skies with night when the sun Is
below the horizon. The change from day
to night, the change from night to day
are of course, consequences of the rota.
tion of the planet on its axis. 1t has
long been desired to learn how far the
period which the planet requires TO conn
plete each turn may agree or disagree
with the time required by the earth for a
like movement. TO put the matter more
definitely, IL may be inquired how far the
period required by Venus to rotate on its
axis corresponds with that period OF
twenty-four hours, or, more accurately,
% hours and 80 minutes, which expresses
the time taken by the earth to complete
one revolution about its axis. The deter
mination of the length of the day and the
ItuKtll Vi tIt nfknt W WlASAt WIG AhAaAAoA-
tants of Mars must accommodate their
domestic arrangements has never admit
ted of much doubt. Indeed, the length
Of the day on Mars to single second of
time Is known. This determination has
been made so accurately because the
marks on Mars are clear enough to be
precisely identified. After the lapse OF
years, or after the lapse OF even centuries,
those marks are still to be seen, without
any doubt whatever, in each revolution
of the planet. But for the study of
length of day and the length OF night on
Venus the face of the beautiful evening
star offers no such facility. This globe
has no well marked features; there are
no definite spots to sully the brilliant
mantle OF sunbeams characteristic OF the
evening star.
One very eminent astr onomer thought
that the day In Venus must be enormous
iy Iong-must, In fact, last for about fif-
teen weeks, while the night which sue
ceeded it had to last for fifteen weeks
more. This discrepancy showed that the
marks on the planets globe Were not
sufficiently definite to solve the problem.
Such marks as could be seen with more
or less distinctness We're most probably
merely clouds in the atmosphere of the
planet, and consequently had no perma-
mence Some other method of solving
the problem not exposed to such difficult
ties was clearly necessary.
A totally new method Of attacking the
question has been applied to Venus dur
ing it's present apparftion by the astrono-
mer Beiopolski. He has adopted
totally different principle. AS the planet
turns round one edge comes toward us
and the other edge goes from us. II the
period be the short one, like our own day,
then the edge which is advancing toward
us will move more rapidly than 1t would
be mo wing II the period were to be ex-