in the sides and base were but little exposed.
Whenever a large mass seemed dangerously near the glass, they applied
an apergetic shock to it and sent it kiting among its fellows. At
these times the Callisto recoiled slightly also, the resulting motion
in either being in inverse 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-darkness--not 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