seen before, but its true
nature was unsuspected. It has a diameter of about 31,700 miles.

Four satellites of Uranus have been discovered, and they present the
remarkable peculiarity that while all the other planets and their
satellites revolve nearly in one plane, the satellites of Uranus are
nearly at right angles, indicating the presence of some local and
exceptional influence.

NEPTUNE

The study of Uranus soon showed that it followed a path which could not
be accounted for by the influence of the Sun and the other then known
planets. It was suspected, therefore, that this was due to some other
body not yet discovered. To calculate where such a body must be so as to
account for these irregularities was a most complex and difficult, and
might have seemed almost a hopeless, task. It was, however, solved
almost simultaneously and independently by Adams in this country, and Le
Verrier in France.

Neptune, so far as we yet know the out-most of our companions, is 35,000
miles in diameter, and its mean distance from the Sun is 2,780,000,000
miles.

ORIGIN OF THE PLANETARY SYSTEM

The theory of the origin of the Planetary System known as the "Nebular
Hypothesis," which was first suggested by Kant, and developed by
Herschel and Laplace, may be fairly said to have attained a high degree
of probability. The space now occupied by the solar system is supposed
to have been filled by a rotating spheroid of extreme tenuity and
enormous heat, due perhaps to the collision of two originally separate
bodies. The heat, however, having by degrees radiated into space, the
gas cooled and contracted towards a centre, destined to become the Sun.
Through the action of centrifugal force the gaseous matter also
flattened itself at the two poles, taking somewhat the form of a disc.
For a certain time the tendency to contract, and the centrifugal force,
counterbalanced one another, but at length a time came when the latter
prevailed and the outer zone detached itself from the rest of the
sphere. One after another similar rings were thrown off, and then
breaking up, formed the planets and their satellites.

That each planet and satellite did form originally a ring we still have
evidence in the wonderful and beautiful rings of Saturn, which, however,
in all probability will eventually form spherical satellites like the
rest. Thus then our Earth was originally a part of the Sun, to which
again it is destined one day to return. M. Plat