measure his strength against other men's.

It was in 1781 that Herschel made the great discovery which immediately
established his fame as an astronomer, and enabled him to turn from
conducting concerts to the far higher work of professionally observing
the stars. On the night of Tuesday, March 13th, Herschel was engaged
in his usual systematic survey of the sky, a bit at a time, when his
telescope lighted among a group of small fixed stars upon what he at
first imagined to be a new comet. It proved to be no comet, however,
but a true planet--a veritable world, revolving like our own in a
nearly circular path around the sun as centre, though far more remote
from it than the most distant planet then known, Saturn. Herschel
called his new world the Georgium Sidus (King George's star) in honour
of the reigning monarch; but it has since been known as Uranus.
Astronomers all over Europe were soon apprised of this wonderful
discovery, and the path of the freshly found planet was computed by
calculation, its distance from the sun being settled at nineteen times
that of our own earth.

In order faintly to understand the importance attached at the time to
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 n