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account for its size； and for the Nautical Almanac's statement
that there is a 'small and variable' inclination to its orbit；
while Io and Europa revolve exactly in the plane of Jupiter's
equator。〃
They had about as long a journey before them as they had already
made in going from the earth to Jupiter。 The great planet soon
appeared as a huge crescent； since it was between them and the
sun； its moons became as fifth… and sixth…magnitude stars； and in
the evening of the next day Jupiter's disk became invisible to
the unaided eye。 Since there were no way stations； in the shape
of planets or asteroids； between Jupiter and Saturn； they kept
the maximum repulsion on Jupiter as long as possible； and moved
at tremendous speed。 Saturn was somewhat in advance of Jupiter
in its orbit； so that their course from the earth had been along
two sides of a triangle with an obtuse angle between。 During the
next four terrestrial days they sighted several small comets； but
spent most of their time writing out their Jovian experiences。
During the sixth day Saturn's rings； although not as much tilted
as they would be later in the planet's season； presented a most
superb sight； while they spun in the sun's rays。 Soon after this
the eight moons became visible； and； while slightly reducing the
Callisto's speed； they crossed the orbits of Iapetus； Hyperion；
and Titan； when they knew they were but seven hundred and fifty
thousand miles from Saturn。
〃I am anxious to ascertain；〃 said Cortlandt； 〃whether the
composition of yonder rings is similar to that of the comet
through which we passed。 I am sure they shine with more than
reflected light。〃
〃We have been in the habit；〃 said Ayrault； 〃of associating heat
with light； but it is obvious there is something far more subtle
about cometary light and that of Saturn's rings； both of which
seem to have their birth in the intense cold of interplanetary
space。〃
Passing close to Mimas； Saturn's nearest moon； they supplemented
its attraction； after swinging by； by their own strong pull；
bringing their speed down to dead slow as they entered the
outside ring。 At distances often of half a mile they found
meteoric masses； sometimes lumps the size of a house； often no
larger than apples； while small particles like grains of sand
moved between them。 There were two motions。 The ring revolved
about Saturn； and the particles vibrated among themselves；
evidently kept apart by a mutual repulsion； which seemed both to
increase and decrease faster than gravitation； for on approaching
one another they were more strongly repelled than attracted； but
when they separated the repulsion decreased faster than the
attraction； so that after a time divergence ceased； and they
remained at fixed distances。
The Callisto soon became imbued with motion also； but nothing
ever struck it。 When any large mass came unusually near； both it
and their car emitted light； and they rapidly separated。 The
sunlight was not as strong here as it had been when they entered
the comet； and as they penetrated farther they were better able
to observe the omnipresent luminosity。 They were somewhat
puzzled by the approach of certain light…centres； which seemed to
contain nothing but this concentrated brightness。 Occasionally
one of these centres would glow very brightly near them； and
simultaneously recede。 At such times the Callisto also glowed；
and itself recoiled slightly。 At first the travellers could not
account for this； but finally they concluded that the centres
must be meteoric masses consisting entirely of gases； possessing
weight though invisible。
〃We have again to face；〃 said Cortlandt； 〃that singular law that
till recently we did not suppose existed on earth。 All kinds of
suppositions have been advanced in explanation of these rings。
Some writers have their thickness； looked at from the thin edge；
as four hundred miles； some one hundred； and some but forty。 One
astronomer of the nineteenth century； a man of considerable
eminence； was convinced that they consisted of sheets of liquid。
Now； it should be obvious that no liquid could maintain itself
here for a minute； for it would either fall upon the planet as a
crushing hail； or； if dependent for its shape on its own
tenacity； it would break if formed of the toughest steel； on
account of the tremendous weight。 Any number of theories have
been advanced by any number of men； but in weight we have the
rub。 No one has ever shown how these innumerable fragments
maintain themselves at a height of but a few thousand miles above
Saturn； withstanding the giant's gravitation…pull。 Their rate of
revolution； though rapid； does not seem fast enough to sustain
them。 Neither have I ever seen it explained why the small
fragments do not fall upon the large ones； though many
astronomers have pictured the composition of these rings as we
find they exist。 Nor do we know why the molecules of a gas are
driven farther apart by heat； while their activity is also
increased； though if this activity were revolution about one
another to develop the centrifugal； it would not need to be as
strong then as when they are cold and nearer together。 There may
be explanations； but I have found none in any of the literature I
have read。 It seems to me that all this leads to but one
conclusion； viz。： apergy is the constant and visible companion of
gravitation； on these great planets Jupiter and Saturn； perhaps
on account of some peculiar influence they possess； and also in
comets； in the case of large masses； while on earth it appears
naturally only among moleculesthose of gases and every other
substance。〃
〃I should go a step further；〃 said Bearwarden； 〃and say our earth
has the peculiarity； since it does not possess the influence
necessary to generate naturally a great or even considerable
development of apergy。 The electricity of thunderstorms；
northern lights； and other forces seems to be produced freely；
but as regards apergy our planet's natural productiveness appears
to be small。〃
The omnipresent luminosity continued； but the glow was scarcely
bright enough to be perceived from the earth。
〃I believe； however；〃 said Bearwarden； referring to this； 〃that
whenever a satellite passes near these fragments； preferably when
it enters the planet's shadow； since that will remove its own
light； it will create such activity among them as to make the
luminosity visible to the large telescopes or gelatine plates on
earth。〃
〃Now；〃 said Ayrault； 〃that we have evolved enough theories to
keep astronomers busy for some time； if they attempt to discuss
them； I suggest that we alight and leave the abstract for the
concrete。〃
Whereupon they passed through the inner ring and rapidly sank to
the ground。
BOOK III。
CHAPTER I。
SATURN。
Landing on a place about ten degrees north of the equator； so
that they might obtain a good view of the great ringssince ON
the line only the thin edge would be visiblethey opened a
port…hole with the same caution they had exercised on Jupiter。
Again there was a rush of air； showing that the pressure without
was greater than that within； but on this occasion the barometer
stopped at thirty…eight； from which they calculated that the
pressure was nineteen pounds to the square inch on their bodies；
instead of fifteen as at sea…level on earth。 This difference was
so slight that they scarcely felt it。 They also discarded the
apergetic outfits that had been so useful on Jupiter； as
unnecessary here。 The air was an icy blast； and though they
quickly closed the opening； the interior of the Callisto was
considerably chilled。
〃We shall want our winter clothes；〃 said Bearwarden； 〃it might be
more comfortable for us exactly on the equator； though the scene
at night will be far finer here； if we can stand the climate。
Doubtless it will also be warmer soon； for the sun has but just
risen。〃
〃I suspect this is merely one of the cold waves that rush towards
the equator at this season； which corresponds to about the 10th
of our September；〃 replied Cortlandt。 〃The poles of Saturn must
be intensely cold during its long winter of fourteen and three
quarter years； for； the axis being inclined twenty…seven degrees
from the perpendicular of its orbit； the pole turned from the sun
is more shut off from its heat than ours； and in addition to this
the mean distancemore than eight hundred and eighty million
milesis very great。 Since the chemical composition of the air
we have inhaled has not troubled our lungs； it is fair to suppose
we shall have no difficulty in breathing。〃
Having dressed themselves more warmly； and seen by a thermometer
they had placed outside that the temperature was thirty…eight
degrees Fahrenheit； which had seemed very cold compared with the
warmth inside the Callisto； they again opened the port…hole； this
time leaving it open longer。 What they had felt before was
evidently merely a sudden gust； for the air was now comparatively
calm。
Finding that the doctor's prediction as to the suitability