New-York tribune., 1900-08-12

Inc most Conspicuous ODJc[L III l4A~ SF~--~--o
skies for the next week or two will De the
planet Jupiter. After Tuesday the moon Win
not enter into competition until after 10 o'clock
or later. Mercury and Venus set before the sun
does nowadays. Mars is also invisible during the
early part Of the night. Saturn may be found
about thirty degrees to the eastward OF Jupiter
and little lower down in the south: but he IS
much fainter, and there have been no announce
ments regarding him Of late that excite special
interest.
Moreover. the time sor the Perseid meteor
shower is past At best this is feeble
display Instead of being concentrated within
the limits Of a single night and occurring only
once in several years. it is spread out over a
fortnight-the last week OF July and the first
week Of August-and is more brilliant one
year than another And even when the Perseids
are due the chance Of seeing one Of these lazy
yellow celestial wanderers up in the northeast
is not much better than that Of deserving some
unclassided meteor Of a different hue and in
another quarter Of the heavens.
Jupiter is admirably placed just now for OBJ
servation- He becomes visible high up in the
southwest long before any Of the stars can be
detected. Not only is he the largest OF all the
planets. but the rejecting power Of his surface.
or "albedo." is nearly % per cent greater than
that Of the lovely Venus. These two advantages
are offset to be sure. by his greater distance
When Jupiter and Venus are both favorably
situated for comparison. Jupiter always suffers.
But at present he has it all his own way
MARKINGS ON THE SURFACE
The markings which are noted on the surface
of Jupiter. and which undergo more or less
change from time to time. are unique in many
respects When we look at Mars probably
see the solid material composing that rudy
little orb. whereas Venus and Jupiter sup
posed to be clothed in cloud shells which cannot
easily be penetrated by the human gaze But
the markings Venus are irregular in their
distribution and exceedingly faint Those on
Jupiter more systematic and striking al
though their significance is far from being fully
revealed. In the first place there is a general
arrangement of bands at right angles to the
axis; broad equatorial bright zone. a darker
belt on each side of it. and then in still higher
latitudes a northern and southern sub-tropicaI
bright belt, bounded more less distinctly by
an extension Of the darker polar regions
Then tendency of Jupiter's envelope to ar
range itself in streaks is readily expIainabIe by
the inequalities in the planets rotation a patch
near the equator goes around once in about ni1z
hours and fifty minutes. whereas in higher Iati-
tudes more than five minutes additional ara re-
qulred A difference in speed OF 1 in 40 IS
enough to draw out any plastic material ike the
planets cloud filed atmosphere into belts in a
very short time Even the much smaller ineuual-
tiles which are observed further away rom the
equator operate in the same manner. though
more slowly.
Ihe broad general features Just referred TO can
De dlscerned with small glasses. but with larger
instruments much detail is visIbIe-tiny bIacl
ana white spots. diagonal riffs across the dark
DeIts Irregularities along the Iatter's edges and
delicate wisps of vapor OVERLAPPING the bright
81 Ao'e' which' by the way, is sometimes
seen to be divided IongitudinaIIy bv a faint III,
about on the planets equator
THE GREAT RED SPOT.
BY far the largest and most DerD1a,t,,e- ,,,-,
ing on JuDiter is the ..erraat II -