terplanetary 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 t