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comet； and been captured by the immense power of 〃Jupiter； which
might account for the eccentricity of its orbit； or some accident
has happened to rejuvenate it here。 A collision with another
minor planet moving in an orbit that crossed its own； or with the
head of a large comet； would have reconverted it into a star；
perhaps after it had long been cold。 A comet may first have so
changed the course of one of two small bodies as to make them
collide。 This seems to me the most plausible theory。 Over a
hundred years ago the English astronomer； Chambers； wrote of
having found traces of atmosphere in some of these minor planets；
but it was generally thought he was mistaken。 One reason we know
so little about this great swarm of minor planets is； that till
recently none of them showed a disk to the telescope。 Inasmuch
as only their light was visible； they were indistinguishable from
stars； except by their slow motion。 A hundred years ago only
three hundred and fifty had been discovered； our photographic
star…charts have since then shown the number recorded to exceed
one thousand。〃
CHAPTER IV。
PREPARING TO ALIGHT。
That afternoon Ayrault brought out some statistical tables he had
compiled from a great number of books； and also a diagram of the
comparative sizes of the planets。 〃I have been not a little
puzzled at the discrepancies between even the best authors；〃 he
said； 〃scarcely any two being exactly alike； while every decade
has seen accepted theories radically changed。〃 Saying which； he
spread out the result of his labours （shown on the following
pages）； which the three friends then studied。
…
（1） Mean distance from sun in millions of miles
（2） Semimajor axis of orbit； earth's distance as 1
（3） Eccentricity of orbit
（4） Planets inclination of orbit to elliptic
（5） Light at perihelion
（6） Light at apehelion
（7） Heat； earth as 1
（1） （2） （3） （4） （5） （6） （7）
Mercury。。。 36。0 0。387 0。2056 7@0'8〃 10。58 4。59 6。67
Venus。。。。。 67。2 0。723 0。0068 3@23'35〃 1。94 1。91 1。91
The Earth。 92。9 1。000 0。068 0@0'0〃 1。03 0。997 1。00
Mars。。。。。。141。5 1。524 0。0933 1@51'2〃 0。52 0。360 1。43
Asteroids 204。4 to 2。200 0。4 to 5@…35@ 325。2 to 3。500 0。34
Jupiter。。 483。3 5。203 0。0483 1@18'41〃 0。04 0。034 0。037
Saturn。。。 886。0 9。539 0。0561 2@29'40〃 0。012 0。0099 0。011
Uranus。。 1781。9 19。183 0。0463 0@46'20〃 0。0027 0。0025 0。003
Neptune。 2791。6 30。055 0。0090 1@47'2〃 0。0011 0。0011 0。001
…
（1） MOVEMENT IN ORBIT。 Velocity compared with earth as 1。
（2） MOVEMENT IN ORBIT。 Period of revolution in years and days。
（3） MOVEMENT IN ORBIT。 Orbital velocity in miles per second。
（4） Mean diameter in miles
（5） Surface compared with earth as 1。
（6） Volume compared with earth as 1。
（7） Mass compared with earth as 1。
Planets （1） （2） （3） （4） （5） （6） （7）
Mercury。。。。。 0。88 23 to 35 1。6 3；000 0。14 0。056 0。13
Venus。。。。。0。224 1/2 21。9 1。17 7；700 0。94 0。92 0。78
The Earth。。。 1。00 18。5 1。0 7；918 1。00 1。00 1。00
Mars。。。。。。。。 1。88 15。0 0。81 4；230 0。28 0。139 0。124
Asteroids。。。 3。29 。。。。 。。。。 From a few to 6。56
miles to 300
Jupiter。。。。。 11。86 8。1 0。44 86；500 118。3 1309。00 316。0
Saturn。。。。。。 29。46 6。0 0。32 1；000 0。4 760。0 95。0
Uranus。。。。。。 84。02 4。2 0。23 31；900 16。3 65。0 14。7
Neptune。。。。 164。78 3。4 0。18 34；800 19。3 90。0 17。1
…
（1） Length of day。 hrs。 min。 sec。
（2） Length of seasons
（3） DENSITY Compared with earth as 1
（4） DENSITY Compared with water as 1
（5） FORCE OF GRAVITY AT SURFACE OF PLANET Compared with earth as
1。
（6） FORCE OF GRAVITY AT SURFACE OF PLANET Bodies fall in one
second。
（7） Inclination of axis。
Planets （1） （2） （3） （4） （5） （6） （7）
Mercury。 。。。。。。。。 。。。。。。。。。 1。24 7。17 0。85 13。7 。。。。。
Venus。。。 23 21 22 。。。。。。。。 0。92 5。21 0。83 13。4 53＋
The Earth。 。。。。。 Spring； 93 1。00 5。67 1。00 16。09 23 1/2
Summer； 93
Terrestrial days Autumn； 90
Winter；89
Mars。。。 24 37 23 Spring； 191 0。96 2。54 0。38 6。2 27 1/2
Summer； 181
Martian days Autumn； 149
Winter； 147
Asteroids。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。。
Jupiter。 9 55 28 。。。。。。。。。 0。22 1。29 2。55 40。98 1 1/2
Saturn。。10 29 17 。。。。。。。。。 0。13 0。63 1。15 18。53 27
Uranus。 。。。。。。。 。。。。。。。。。 0。18 1。41 0。91 14。6 102（？）
Neptune。。。。。。。。。 。。。。。。。。。 0。20 0 0。88 14。2 。。。。。
…
〃You see；〃 Ayrault explained； 〃on Jupiter we shall need our
apergetic outfits to enable us to make long marches； while on
Saturn they will not be necessary； the increase in our weight as
a result of that planet's size being considerably less than the
usual load carried by the Roman soldier。〃
〃I do not imagine；〃 said Cortlandt； 〃we should long be troubled
by gravitation without our apergetic outfits even on Jupiter；
for； though our weight will be more than doubled； we can take off
one quarter of the whole by remaining near the equator； their
rapid rotation having apparently been given providentially to all
the large planets。 Nature will adapt herself to this change； as
to all others； very readily。 Although the reclamation of the
vast areas of the North American Arctic Archipelago； Alaska；
Siberia； and Antarctic Wilkes Land； from the death…grip of the
ice in which they have been held will relieve the pressure of
population for another century； at the end of that time it will
surely be felt again； it is therefore a consolation to feel that
the mighty planets Jupiter and Saturn； which we are coming to
look upon as our heritage； will not crush the life out of any
human beings by their own weight that may alight upon them。〃
Before going to bed that evening they decided to be up early the
next day； to study Jupiter； which was already a brilliant object。
The following morning； on awakening； they went at once to their
observatory； and found that Jupiter's disk was plainly visible to
the naked eye； and before night it seemed as large as the full
moon。
They then prepared to check the Callisto's headlong speed； which
Jupiter's attraction was beginning to increase。 When about two
million miles from the great planet； which was considerably on
their left； they espied Callisto ahead and slightly on their
right； as Deepwaters had calculated it would be。 Applying a mild
repulsion to thiswhich was itself quite a world； with its
diameter of over three thousand miles； though evidently as cold
and dead as the earth's old moonthey retarded their forward
rush； knowing that the resulting motion towards Jupiter would be
helped by the giant's pull。 Wishing to be in good condition for
their landing； they divided the remainder of the night into
watches； two going to sleep at a time； the man on duty standing
by to control the course and to get photographic negatives； on
which； when they were developed； they found two crescent…shaped
continents； a speckled region； and a number of islands。 By 7 A。
M。； according to Eastern standard time； they were but fifty
thousand miles from Jupiter's surface； the gigantic globe filling
nearly one side of the sky。 In preparation for a sally； they got
their guns and accoutrements ready； and then gave a parting
glance at the car。 Their charge of electricity for developing
the repulsion seemed scarcely touched； and they had still an
abundant supply of oxygen and provisions。 The barometer
registered twenty…nine inches； showing that they had not lost
much air in the numerous openings of the vestibule。 The pressure
was about what would be found at an altitude of a few hundred
feet； part of the rarefaction being no doubt due to the fact that
they did not close the windows until at a considerable height
above Van Cortlandt Park。
They saw they should alight in a longitude on which the sun had
just risen； the rocky tops of the great mountains shining like
helmets in its rays。 Soon they felt a sharp checking of their
forward motion； and saw； from the changed appearance of the stars
and the sun； that they had entered the atmosphere of their new
home。
Not even did Columbus； standing at the prow of the Santa Maria；
with the New World before him； feel the exultation and delight
experienced by these latter…day explorers of the twenty…first
century。 Their first adventures on landing the reader already
knows。
CHAPTER V。
EXPLORATION AND EXCITEMENT。
When they awoke； the flowers were singing with the volume of a
cathedral organ； the chant rising from all around them； and the
sun was already above the horizon。 Finding a deep natural
spring； in which the water was at about blood…heat； they prepared
for brea