EXCURSIONS ON THE PLANETS—RUDAUX 189 
because of the great heat of the sun, but travel to Venus, farther off 
from the sun. Seen from Mercury, Venus at certain times would 
appear a truly blinding star. 
Again we have reached ’a planet about which we know very little. 
It appears from without of a brilliant whiteness, but we can detect 
no detail upon it probably because its thick cloudy atmosphere hides 
its soil from our eyes. Some astronomers believe that this atmos- 
phere is very rich in water vapor, others that it contains none! 
At any rate the density of its atmosphere is very great, almost double 
that of ours. Upon the surface of Venus, covered with this dense 
atmosphere, diffusing the intense light from the enormous sun as seen 
from there, a sort of luminous and troubled fog must singularly limit 
the range of vision, doubtless preventing the enjoyment of any 
extended landscape. What are these landscapes? In lieu of any- 
thing better, let us suppose there exists here a surface with some land 
but much water. Through the dense atmosphere, the stars are either 
only slightly or not at all visible. If the sun can be observed at set- 
ting, the phenomena of refraction will be noted as on the earth but 
much more in evidence, modifying strangely the appearance of the 
solar disk. (PI. 6, fig. 2.) 
‘Farther away than the earth from the sun, upon the planet Mars, 
we should feel more at home. Day and night are scarcely longer 
than on the earth. Through an atmosphere very similar. to ours 
although less dense, the stars will appear in splendor, enriched with 
two small moons. ‘The smaller of these not only will appear to move 
with great speed but in an opposite direction from the apparent 
movement of the stars; indeed it revolves about Mars faster than the 
latter rotates upon its Aig At certain epochs, either in the morning 
or evening, the earth will be visible as morning or evening star, re- 
spetetrety. br illiant in the dawn or evening Ae the latter of ae 
duration because of the rarity of the Martian so uae The sky 
will appear darker during the daytime and the sun, a third smaller 
than from the earth, will illumine less brilliantly the doubtless more 
monotonous landscape. The most reliable observations indicate a 
ground with very little relief, probably almost everywhere level, 
cut here and there with immense swamps. Incontestably in every 
respect we should feel the most at home on this planet. 
But let us pursue our journey toward the giant planets. Upon 
them—Jupiter, Saturn, Uranus, and Neptune—we would no longer 
find ourselves upon solid ground, at least in the literal sense of the 
word. For it is very probable that these worlds are yet fluid, at any 
rate in a condition which would not admit of a solid surface: Tt 
would be impossible to find a landing place. Because of this cir- 
cumstance, we will suppose ourselves changed into immaterial beings 
though still retaining our organs of sight. If Jupiter should possess 
20837—27——_14. 
