they do at the poles； by reason of the centrifugal force。
Influenced by this fact； and also because they were 483；000；000
miles from the sun； instead of 92；000；000 as on earth； they had
steered for the northern limit of Jupiter's tropics。 And； in
addition to this； they could easily apply the apergetic power in
any degree to themselves when beyond the limits of the Callisto；
and so be attracted to any extent； from twice the pull they
receive from gravitation on earth to almost nothing。
Bearwarden and Ayrault shouldered their rifles； while Dr。
Cortlandt took a repeating shot…gun with No。 4 shot； and； having
also some hunting…knives and a sextant； all three set out in a
northwesterly direction。 The ground was rather soft； and a warm
vapor seemed to rise from it。 To the east the sky was veiled by
dense clouds of smoke from the towering volcanoes； while on their
left the forest seemed to extend without limit。 Clumps of huge
ferns were scattered about； and the ground was covered with
curious tracks。
〃Jupiter is evidently passing through a Carboniferous or Devonian
period such as existed on earth； though； if consistent with its
size； it should be on a vastly larger scale；〃 said the doctor。
〃I never believed in the theory；〃 he continued； 〃that the larger
the planet the smaller should be its inhabitants； and always
considered it a makeshift； put forward in the absence of definite
knowledge； the idea being apparently that the weight of very
large creatures would be too great for their strength。 Of the
fact that mastodons and creatures far larger than any now living
on earth existed there； we have absolute proof； though
gravitation must have been practically the same then as now。〃
Just here they came upon a number of huge bones； evidently the
remains of some saurian； and many times the size of a grown
crocodile。 On passing a growth of most luxuriant vegetation；
they saw a half…dozen sacklike objects； and drawing nearer
noticed that the tops began to swell； and at the same time became
lighter in colour。 Just as the doctor was about to investigate
one of them with his duck…shot； the enormously inflated tops of
the creatures collapsed with a loud report； and the entire group
soared away。 When about to alight； forty yards off； they
distended membranous folds in the manner of wings； which checked
their descent； and on touching the ground remained where they
were without rebound。
〃We expected to find all kinds of reptiles and birds；〃 exclaimed
the doctor。 〃But I do not know how we should class those
creatures。 They seem to have pneumatic feet and legs； for their
motion was certainly not produced like that of frogs。〃
When the party came up with them the heads again began to swell。
〃I will perforate the air…chamber of one；〃 said Col。 Bearwarden；
withdrawing the explosive cartridge from the barrel of his rifle
and substituting one with a solid ball。 〃This will doubtless
disable one so that we can examine it。〃
Just as they were about to rise； he shot the largest through the
neck。 All but the wounded one； soared off； while Bearwarden；
Ayrault； and Cortlandt approached to examine it more closely。
〃You see；〃 said Cortlandt； 〃this vertebratefor that is as
definitely as we can yet describe itforces a great pressure of
air into its head and neck； which； by the action of valves； it
must allow to rush into its very rudimentary lower extremities；
distending them with such violence that the body is shot upward
and forward。 You may have noticed the tightly inflated portion
underneath as they left the ground。〃
While speaking he had moved rather near； when suddenly a
partially concealed mouth opened； showing the unmistakable tongue
and fangs of a serpent。 It emitted a hissing sound； and the
small eyes gleamed maliciously。
〃Do you believe it is a poisonous species？〃 asked Ayrault。
〃I suspect it is；〃 replied the doctor； 〃for； though it is
doubtless able to leap with great accuracy upon its prey； we saw
it took some time to recharge the upper air…chamber； so that；
were it not armed with poison glands； it would fall an easy
victim to its more powerful and swifter contemporaries； and would
soon become extinct。〃
〃As it will be unable to spring for some time；〃 said Bearwarden；
〃we might as well save it the disappointment of trying；〃 and；
snapping the used shell from his rifle； he fired an explosive
ball into the reptile； whereupon about half the body disappeared；
while a sickening odour arose。 Although the sun was still far
above the horizon； the rapidity with which it was descending
showed that the short night of less than five hours would soon be
upon them； and though short it might be very dark； for they were
in the tropics； and the sun； going down perpendicularly； must
also pass completely around the globe； instead of； as in northern
latitudes on earth in summer； approaching the horizon obliquely；
and not going far below it。 A slight and diffused sound here
seemed to rise from the ground all about them； for which they
could not account。 Presently it became louder； and as the sun
touched the horizon； it poured forth in prolonged strains。 The
large trumpet…shaped lilies； reeds； and heliotropes seemed fairly
to throb as they raised their anthem to the sky and the setting
sun； while the air grew dark with clouds of birds that gradually
alighted on the ground； until； as the chorus grew fainter and
gradually ceased； they flew back to their nests。 The three
companions had stood astonished while this act was played。 The
doctor then spoke：
〃This is the most marvellous development of Nature I have seen；
for its wonderful divergence from； and yet analogy to； what takes
place on earth。 You know our flowers offer honey； as it were； as
bait to insects； that in eating or collecting it they may catch
the pollen on their legs and so carry it to other flowers；
perhaps of the opposite sex。 Here flowers evidently appeal to
the sense of hearing instead of taste； and make use of birds； of
which there are enormous numbers； instead of winged insects； of
which I have seen none； one being perhaps the natural result of
the other。 The flowers have become singers by long practice； or
else； those that were most musical having had the best chance to
reproduce； we have a neat illustration of the 'survival of the
fittest。' The sound is doubtless produced by a shrinking of the
fibres as the sun withdraws its heat； in which case we may expect
another song at sunrise； when the same result will be effected by
their expanding。〃
Searching for a camping…place in which to pass the coming hours；
they saw lights flitting about like will…o'…the…wisps； but
brighter and intermittent。
〃They seem to be as bright as sixteen…candle…power lamps； but the
light is yellower； and appears to emanate from a comparatively
large surface； certainly nine or ten inches square；〃 said the
doctor。
They soon gave up the chase； however； for the lights were
continually moving and frequently went out。 While groping in the
growing darkness； they came upon a brown object about the size of
a small dog and close to the ground。 It flew off with a humming
insect sound； and as it did so it showed the brilliant
phosphorescent glow they had observed。
〃That is a good…sized fire…fly；〃 said Bearwarden。 〃Evidently the
insects here are on the same scale as everything else。 They are
like the fire…flies in Cuba； which the Cubans are said to put
into a glass box and get light enough from to read by。 Here they
would need only one； if it could be induced to give its light
continuously。〃
Having found an open space on high ground； they sat down； and
Bearwarden struck his repeater； which； for convenience； had been
arranged for Jupiter time； dividing the day into ten hours；
beginning at noon； midnight being therefore five o'clock。
〃Twenty minutes past four；〃 said he； 〃which would correspond to
about a quarter to eleven on earth。 As the sun rises at
half…past seven； it will be dark about three hours； for the time
between dawn and daylight will； of course； be as short as that we
have just experienced between sunset and night。〃
〃If we stay here long；〃 said the doctor； 〃I suppose we shall
become accustomed； like sailors； to taking our four； or in this
case five； hours on duty； and five hours off。〃
〃Or；〃 added Ayrault； 〃we can sleep ten consecutive hours and take
the next ten for exploring and hunting； having the sun for one
half the time and the moons for the other。〃
Bearwarden and Cortlandt now rolled themselves in their blankets
and were soon asleep； while Ayrault； whose turn it was to watch
till the moons rosefor they had not yet enough confidence in
their new domain to sleep in darkness simultaneouslyleaned his
back against a rock and lighted his pipe。 In the distance he saw
the torrents of fiery lava from the volcanoes reflected in the
sky； and faintly heard their thunderous crashes； while the
fire…flies twinkled unconcernedly in the hollow； and the night
winds swayed the fernlike branches。 Then he gazed at the earth；
which； but little above the horizon； shone with a faint but
steady ray； and his mind's eye ran beyond his natural vision
while he pictured to himself the girl of his heart； wishing that
by some communion of spirits he might convey his thoughts to her；
and receive hers。 It was now the first week of January on earth。
He could almost see her house and the snow…clad trees in the
park； and knew that at that hour she was dressing for dinner； and
hoped and believed that he was in her heart。 While he thus
mused； one moon after another rose； each at a different phase；
till three were at once in the sky。 Adjusting the electric
protection… wires that were to paralyze any creature that
attempted to come within the circle； and would arouse them by
ringing a bell； he knocked the ashes from his pipe； rolled
himself in a blanket； and was soon asleep beside his friends。
CHAPTER II。
ANTECEDENTAL。
〃Come in！〃 sounded a voice； as Dr。 Cortlandt and Dick Ayrault
tapped at the door of the President