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ratio to its weight。 There was constant and incessant movement
among the individual fragments； but it was not rotary。 Nothing
seemed to be revolving about anything else； all were moving；
apparently swinging back and forth； but no collisions took place。
When the separate particles got more than a certain distance
apart they reapproached one another； but when seemingly within
about one hundred diameters of each other they swung off in some
other direction。 The motion was like that of innumerable
harp…strings； which may approach but never strike one another。
After a time the Callisto seemed to become endowed with the same
property that the fragments possessed； for it and they repelled
one another； on a near approach； after which nothing came very
near。
Much of the material was like slag from a furnace； having
evidently been partly fused。 Whether this heat was the result of
collision or of its near approach to the sun at perihelion； they
could not tell； though the latter explanation seemed most simple
and probable。 When at about the centre of the nucleus they were
in semi…darknessnot twilight； for any ray that succeeded in
penetrating was dazzlingly brilliant； and the shadows； their own
included； were inky black。 As they approached the farther side
and the sunlight decreased； they found that a diffused luminosity
pervaded everything。 It was sufficiently bright to enable them
to see the dark side of the meteoric masses； and； on emerging
from the nucleus in total darkness； they found the shadow
stretching thousands of miles before them into space。
〃I now understand；〃 said Bearwarden； 〃why stars of the sixth and
seventh magnitude can be seen through thousands of miles of a
comet's tail。 It is simply because there is nothing in it。 The
reason ANY stars are obscured is because the light in the tail；
however faint； is brighter than they； and that light is all that
the caudal appendage consists of； though what produces it I
confess I am unable to explain。 I also see why the tail always
stretches away from the sun； because near by it is overwhelmed by
the more powerful light； in fact； I suspect it is principally in
the comet's shadow that the tail is visible。 It is strange that
no one ever thought of that before； or that any one feared the
earth's passing through the tail of a comet。 It is obvious to me
now that if there were any material substance； any gas； however
rarefied； in this hairlike＇1＇ accompaniment； it would immediately
fall to the comparatively heavy head；
and surround that as a centre。〃
＇1＇ Comet means literally a hair。
〃How； then；〃 asked Cortlandt； 〃do you account for the spaces
between those stones？ However slight gravitation might be
between some of the grains； if it existed at all； or was
unopposed by some other force； with sufficient timeand they
have eternityevery comet would come together like a planet into
one solid mass。 Perhaps some similar force maintains gases in
the distended tail； though I know of no such； or even any
analogous manifestation on earth。 If the law on which we have
been brought up； that 'every atom in the universe attracts every
other atom；' were without exceptions or modifications； that comet
could not continue to exist in its present form。 Until we get
some additional illustration； however； we shall be short of data
with which to formulate any iconoclastic hypothesis。 The source
of the light； I must admit； also puzzles me greatly。 There is
certainly no heat to which we can attribute it。〃
Having gone beyond the fragments； they applied a strong repulsion
charge to the comet； creating thereby a perfect whirlpool among
its particles； and quickly left it。 Half an hour later they
again shut off the current； as the Callisto's speed was
sufficient。
For some time they had been in the belt of asteroids； but as yet
they had seen none near。 The morning following their experience
with the comet； however； they went to their observatory after
breakfast as usual； and； on pointing their glasses forward；
espied a comparatively large body before them； a little to their
right。
〃That must be Pallas；〃 said Cortlandt； scrutinizing it closely。
〃It was discovered by Olbers； in 1802； and was the second
asteroid found； Ceres having been the first； in 1801。 It has a
diameter of about three hundred miles； being one of the largest
of these small planets。 The most wonderful thing about it is the
inclination of its orbitthirty…five degreesto the plane of
the ecliptic； which means that at each revolution in its orbit；
it swings that much above and below the imaginary plane cutting
the sun at its equator； from which the earth and other larger
planets vary but little。 This no doubt is due to the near
approach and disturbing attraction of some large comet； or else
it was flung above or below the ordinary plane in the catastrophe
that we think befell the large planet that doubtless formerly
existed where we now find this swarm。 You can see that its path
makes a considerable angle to the plane of the ecliptic； and that
it is now about crossing the line。〃
It soon presented the phase of a half moon； but the waviness of
the straight line； as in the case of Venus and Mercury； showed
that the size of the mountains must be tremendous compared with
the mass of the body； some of them being obviously fifteen miles
high。 The intense blackness of the shadows； as on the moon；
convinced them there was no trace of atmosphere。
〃There being no air；〃 said Cortlandt； 〃it is safe to assume there
is no water； which helps to account for the great inequalities on
the body's surface； since the mountains will seem higher when
surrounded by dry ocean… bottom than they would if water came
halfway up their sides。 Undoubtedly； however； the main cause of
their height is the slight effect of gravitation on an asteroid；
and the fact that the shrinking of the interior； and consequent
folding of the crust in ridges； may have continued for a time
after there was no longer water on the surface to cut them down。
〃The temperature and condition of a body；〃 continued Cortlandt；
〃seem to depend entirely on its size。 In the sun we have an
incandescent； gaseous star； though its spots and the colour of
its rays show that it is becoming aged； or； to be more accurate；
advanced in its evolutionary development。 Then comes a great
jump； for Jupiter has but about one fourteen…hundredth of the
mass of the sun； and we expect to find on it a firm crust； and
that the planet itself is at about the fourth or fifth period of
development； described by Moses as days。 Saturn is doubtless
somewhat more advanced。 The earth we know has been habitable
many hundreds of thousands or millions of years； though three
fourths of its surface is still covered by water。 In Mars we see
a further step； three fourths of its surface being land。 In
Mercury； could we study it better； or in the larger satellites of
Jupiter or Saturn； we might find a stepping…stone from Mars to
the moon； perhaps with no water； but still having air； and being
habitable in all other respects。 In our own satellite we see a
world that has died； though its death from an astronomical point
of view is comparatively recent； while this little Pallas has
been dead longer； being probably chilled through and through。
From this I conclude that all bodies in the solar system had one
genesis； and were part of the same nebulous mass。 But this does
not include the other systems and nebulae； for； compared with
them； our sun； as we have seen； is itself advanced and small
beside such stars as Sirius having diameters of twelve million
miles。〃
As they left Pallas between themselves and the sun； it became a
crescent and finally disappeared。
Two days later they sighted another asteroid exactly ahead。 They
examined it closely； and concluded it must be Hilda； put down in
the astronomies as No。 153； and having almost the greatest mean
distance of any of these small bodies from the sun。
When they were so near that the disk was plainly visible to the
unaided eye； Hilda passed between them and Jupiter； eclipsing it。
To their surprise； the light was not instantly shut off； as when
the moon occults a star； but there was evident refraction。
〃By George！〃 said Bearwarden； 〃here is an asteroid that HAS an
atmosphere。〃
There was no mistaking it。 They soon discovered a small ice…cap
at one pole； and then made out oceans and continents； with
mountains； forests； rivers； and green fields。 The sight lasted
but a few moments before they swept by； but they secured several
photographs； and carried a vivid impression in their minds。
Hilda appeared to be about two hundred miles in diameter。
〃How do you account for that living world；〃 Bearwarden asked
Cortlandt； 〃on your theory of size and longevity？〃
〃There are two explanations；〃 replied Cortlandt； 〃if the theory；
as I still believe； is correct。 Hilda has either been brought to
this system from some other less matured； in the train of a
comet； and been captured by the immense power of 〃Jupiter； which
might account for the eccentricity of its orbit； or some acci