mathematician can push this inquiry a little farther, and he can study
how this fluid would behave under such circumstances. His symbols can
pursue the subject into the intricacies which cannot be described in
general language. The mathematician finds that waves would originate in
the supposed fluid, and that as these waves would lead to disruption of
the rings, the fluid theory must be abandoned.

But we can still make one or two more suppositions. What if it be really
true that the ring consist of an incredibly large number of concentric
rings, each animated precisely with the velocity which would be suitable
to the production of a centrifugal force just adequate to neutralise the
attraction? No doubt this meets many of the difficulties: it is also
suggested by those observations which have shown the presence of several
dark lines on the ring. Here again dynamical considerations must be
invoked for the reply. Such a system of solid rings is not compatible
with the laws of dynamics.

We are, therefore, compelled to make one last attempt, and still further
to subdivide the ring. It may seem rather startling to abandon entirely
the supposition that the ring is in any sense a continuous body, but
there remains no alternative. Look at it how we will, we seem to be
conducted to the conclusion that the ring is really an enormous shoal of
extremely minute bodies; each of these little bodies pursues an orbit of
its own around the planet, and is, in fact, merely a satellite. These
bodies are so numerous and so close together that they seem to us to be
continuous, and they may be very minute--perhaps not larger than the
globules of water found in an ordinary cloud over the surface of the
earth, which, even at a short distance, seems like a continuous body.

Until a few years ago this theory of the constitution of Saturn's rings,
though unassailable from a mathematical point of view, had never been
confirmed by observation. The only astronomer who maintained that he had
actually seen the rings rotate was W. Herschel, who watched the motion
of some luminous points on the ring in 1789, at which time the plane of
the ring happened to pass through the earth. From these observations
Herschel concluded that the ring rotated in ten hours and thirty-two
minutes. But none of the subsequent observers, even though they may have
watched Saturn with instruments very superior to that used by Herschel,
were ever able to succeed in verifying h