Herschel's observation of this very remote and seemingly petty world, we
must remember that up to that date all the planets which circle round
our own sun had been familiarly known to everybody from time immemorial.
To suggest that there was yet another world belonging to our system
outside the path of the furthest known planet would have seemed to most
people like pure folly. Since then, we have grown quite accustomed to
the discovery of a fresh small world or two every year, and we have even
had another large planet (Neptune), still more remote than Herschel's
Uranus, added to the list of known orbs in our own solar system. But in
Herschel's day, nobody had ever heard of a new planet being discovered
since the beginning of all things. A hundred years before, an Italian
astronomer, it is true, had found out four small moons revolving round
Saturn, besides the big moon then already known; but for a whole
century, everybody believed that the solar system was now quite fully
explored, and that nothing fresh could be discovered about it. Hence
Herschel's observation produced a very different effect from, say, the
discovery of the two moons which revolve round Mars, in our own day.
Even people who felt no interest in astronomy were aroused to attention.
Mr. Herschel's new planet became the talk of the town and the subject of
much admiring discussion in the London newspapers. Strange, indeed, that
an amateur astronomer of Bath, a mere German music-master, should have
hit upon a planet which escaped the sight even of the king's own
Astronomer Royal at Greenwich.

Of course there were not people wanting who ascribed this wonderful
discovery of Herschel's to pure chance. If he hadn't just happened to
turn his telescope in that particular direction on that particular
night, he wouldn't have seen this _Georgium Sidus_ they made such a
fuss about at all. Quite so. And if he hadn't built a twenty-foot
telescope for himself, he wouldn't have turned it anywhere at any time.