eed it would be alien to my
intention to write a complete history about all these researches
which I have gradually brought to even greater perfection, yet on
many occasions, especially whenever I was confronted by some
particularly serious problem, I thought that the first methods which
I employed ought not to be entirely suppressed. Nay, rather, in
addition to the solutions of the principal problems, I have in this
work followed out many questions which presented themselves to me, in
the course of a long study of the motions of the heavenly bodies in
conic sections, as being particularly worthy of attention, whether on
account of the neatness of the analysis, or more especially by reason
of their practical utility. Yet I have always given the greater care
to subjects which I have made my own, merely noticing by the way
well-known facts where connection of thought seemed to demand it."

[Sidenote: Rediscovery of Ceres.]

[Sidenote: Another planet found.]

These words do not explain in any way the methods introduced by Gauss, but
they give us some notion of the flavour of the work. Aided by these
brilliant researches, the little planet was found on the last day of the
year by Von Zach at Gotha, and on the next night, independently, by Olbers
at Bremen. But, before this success, there had been an arduous search,
which led to a curious consequence. Olbers had made himself so familiar
with all the small stars along the track which was being searched for the
missing body, that he was at once struck by the appearance of a stranger
near the spot where he had just identified Ceres. At first he thought this
must be some star which had blazed up to brightness; but he soon found
that it also was moving, and, to the great bewilderment of the
astronomical world, it proved to be another planet revolving round the sun
at a distance nearly the same as the former. This was an extraordinary and
totally unforeseen occurrence. The world had been prepared for _one_
planet; but here were _two_!

[Sidenote: Hypothesis of many fragments.]

The thought occurred to Olbers that they were perhaps fragments of a
single body which had been blown to pieces by some explosion, and that
there might be more of the pieces; and he therefore suggested as a guide
for finding others that, since by the known laws of gravitation, bodies
which circle round the sun return periodically to their