ing. Professor Keeler's beautiful discovery has since been
verified by repeated observations at the Allegheny, Lick, Paris, and
Pulkova Observatories; the actual velocities resulting from the observed
displacements of the lines have been measured and found to agree well
(within the limits of the errors of observation) with the calculated
velocities, so that this brilliant confirmation of the mathematical
deductions of Clerk Maxwell is raised beyond the possibility of doubt.

The spectrum of Saturn is so faint that only the strongest lines of the
solar spectrum can be seen in it, but the atmosphere of the planet seems
to exert a considerable amount of general absorption in the blue and
violet parts of the spectrum, which is especially strong near the
equatorial belt, while a strong band in the red testifies to the density
of the atmosphere. This band is not seen in the spectrum of the rings,
around which there can therefore be no atmosphere.

As Saturn's ring is itself unique, we cannot find elsewhere any very
pertinent illustration of a structure so remarkable as that now claimed
for the ring. Yet the solar system does show some analogous phenomena.
There is, for instance, one on a very grand scale surrounding the sun
himself. We allude to the multitude of minor planets, all confined
within a certain region of the system. Imagine these planets to be
vastly increased in number, and those orbits which are much inclined to
the rest flattened down and otherwise adjusted, and we should have a
ring surrounding the sun, thus producing an arrangement not dissimilar
from that now attributed to Saturn.

It is tempting to linger still longer over this beautiful system, to
speculate on the appearance which the ring would present to an
inhabitant of Saturn, to conjecture whether it is to be regarded as a
permanent feature of our system in the same way as we attribute
permanence to our moon or to the satellites of Jupiter. Looked at from
every point of view, the question is full of interest, and it provides
occupation abundant for the labours of every type of astronomer. If he
be furnished with a good telescope, then has he ample duties to fulfil
in the task of surveying, of sketching, and of measuring. If he be one
of those useful astronomers who devote their energies not to actual
telescopic work, but to forming calculations based on the observations
of others, then the beautiful system of Saturn provides copious
material. He has