Chapter IV: Mars, a World More Advanced Than Ours 85

Resemblances between Mars and the earth--Its seasons and its
white polar caps--Peculiar surface markings--Schiaparelli's
discovery of the canals--His description of their appearance
and of their duplication--Influence of the seasons on the
aspect of the canals--What are the canals?--Mr. Lowell's
observations--The theory of irrigation--How the inhabitants
of Mars are supposed to have taken advantage of the annual
accession of water supplied by the melting of the polar
caps--Wonderful details shown in charts of Mars--Curious
effects that may follow from the small force of gravity
on Mars--Imaginary giants--Reasons for thinking that
Mars may be, in an evolutionary sense, older than the
earth--Speculations about interplanetary signals from
Mars, and their origin--Mars's atmosphere--The question of
water--The problem of temperature--Eccentricities of Mars's
moons

CHAPTER V

_THE ASTEROIDS, A FAMILY OF DWARF WORLDS_ 129

Only four asteroids large enough to be measured--Remarkable
differences in their brightness irrespective of size--Their
widely scattered and intermixed orbits--Eccentric orbit of
Eros--the nearest celestial body to the earth except the
moon--Its existence recorded by photography before it was
discovered--Its great and rapid fluctuations in light, and
the curious hypotheses based upon them--Is it a fragment of
an exploded planet?--The startling theory of Olbers as to
the origin of the asteroids revived--Curious results of the
slight force of gravity on an asteroid--An imaginary visit
to a world only twelve miles in diameter

CHAPTER VI

_JUPITER, THE GREATEST OF KNOWN WORLDS_ 160

Jupiter compared with our globe--His swift rotation on his
axis--Remarkable lack of density--The force of gravity on
Jupiter--Wonderful clouds--Strange phenomena of the great
belts--Brilliant display of colors--The great red spot
and the many theories it has given rise to--Curious facts
about the varying rates of rotation of the huge planet's
surface--The theory of a hidden world in Jupiter--When
Jupiter was a companion star to the sun--The miracle of
world-making before our eyes--Are Jupiter's satellites
habitable?--Magnificent spectacles in the Jovian system

CHAPTER VII

_SATURN, A PRODIGY AMONG PLANETS_ 185

The wonder of the great rings--Saturn's great distance and
long year--The least dense of all the planets--It would
float in water--What kind of a world is it?--Sir Humphry
Davy's imaginary inhabitants of Saturn--Facts about the
rings, which are a phenomenon unparalleled in the visible
universe--The surprising nature of the rings, as revealed
by mathematics and the spectroscope--The question of their
origin and ultimate fate--Dr. Dick's idea of their
habitability--Swedenborg's curious description of the
appearance of the rings from Saturn--Is Saturn a globe of
vapor, or of dust?--The nine satellites and "Roche's
limit"--The play of spectacular shadows in the Saturnian
system--Uranus and Neptune--Is there a yet undiscovered
planet greater than Jupiter?