onsiderable accuracy! We do not
know what can have suggested the latter guess. A few years ago any
astronomer reading the voyage to Laputa would have said this was absurd.
There might be two satellites to Mars, no doubt; but to say that one of
them revolves in ten hours would be to assert what no one could believe.
Yet the truth has been even stranger than the fiction.

And now we must bring to a close our account of this beautiful and
interesting planet. There are many additional features over which we are
tempted to linger, but so many other bodies claim our attention in the
solar system, so many other bodies which exceed Mars in size and
intrinsic importance, that we are obliged to desist. Our next step will
not, however, at once conduct us to the giant planets. We find outside
Mars a host of objects, small indeed, but of much interest; and with
these we shall find abundant occupation for the following chapter.

CHAPTER XI.

THE MINOR PLANETS.

The Lesser Members of our System--Bode's Law--The Vacant Region in
the Planetary System--The Research--The Discovery of Piazzi--Was
the small Body a Planet?--The Planet becomes Invisible--Gauss
undertakes the Search by Mathematics--The Planet Recovered--Further
Discoveries--Number of Minor Planets now known--The Region to be
Searched--The Construction of the Chart for the Search for Small
Planets--How a Minor Planet is Discovered--Physical Nature of the
Minor Planets--Small Gravitation on the Minor Planets--The Berlin
Computations--How the Minor Planets tell us the Distance of the
Sun--Accuracy of the Observations--How they may be
Multiplied--Victoria and Sappho--The most Perfect Method.

In our chapters on the Sun and Moon, on the Earth and Venus, and on
Mercury and Mars, we have been discussing the features and the movements
of globes of vast dimensions. The least of all these bodies is the moon,
but even that globe is 2,000 miles from one side to the other. In
approaching the subject of the minor planets we must be prepared to find
objects of dimensions quite inconsiderable in comparison with the great
spheres of our system. No doubt these minor planets are all of them some
few miles, and some of them a great many miles, in diameter. Were they
close to the earth they would be conspicuous, and even splendid,
objects; but as they are so distant they do not, even in our greatest
telescopes, become very remarka