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to sit by her brother, and enliven the time by reading stories aloud, sometimes pausing to feed
him with a spoon while his hands were engaged on the task from which he could not desist for
a moment.
When mathematical work had to be done Caroline was ready for it; she had taught herself
sufficient to enable her to perform the kind of calculations, not, perhaps, very difficult ones,
that Herschel's work required; indeed, it is not too much to say that the mighty life-work
which this man was enabled to perform could never have been accomplished had it not been
for the self- sacrifice of this ever-loving and faithful sister. When Herschel was at the telescope
at night, Caroline sat by him at her desk, pen in hand, ready to write down the notes of the
observations as they fell from her brother's lips. This was no insignificant toil. The telescope
was, of course, in the open air, and as Herschel not unfrequently continued his observations
throughout the whole of a long winter's night, there were but few women who could have
accomplished the task which Caroline so cheerfully executed. From dusk till dawn, when the
sky was clear, were Herschel's observing hours, and what this sometimes implied we can
realise from the fact that Caroline assures us she had sometimes to desist because the ink had
actually frozen in her pen. The night's work over, a brief rest was taken, and while William had
his labours for the day to attend to, Caroline carefully transcribed the observations made
during the night before, reduced all the figures and prepared everything in readiness for the
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observations that were to follow on the ensuing evening.
But we have here been anticipating a little of the future which lay before the great
astronomer; we must now revert to the history of his early work, at Bath, in 1774, when
Herschel's scrutiny of the skies first commenced with an instrument of his own manufacture.
For some few years he did not attain any result of importance; no doubt he made a few
interesting observations, but the value of the work during those years is to be found, not in
any actual discoveries which were accomplished, but in the practice which Herschel obtained
in the use of his instruments. It was not until 1782 that the great achievement took place by
which he at once sprang into fame.
It is sometimes said that discoveries are made by accident, and, no doubt, to a certain extent,
but only, I fancy to a very small extent, this statement may be true. It is, at all events, certain
that such lucky accidents do not often fall to the lot of people unless those people have done
much to deserve them. This was certainly the case with Herschel. He appears to have formed
a project for making a close examination of all the stars above a certain magnitude. Perhaps
he intended to confine this research to a limited region of the sky, but, at all events, he seems
to have undertaken the work energetically and systematically. Star after star was brought to
the centre of the field of view of his telescope, and after being carefully examined was then
displaced, while another star was brought forward to be submitted to the same process. In the
great majority of cases such observations yield really nothing of importance; no doubt even
the smallest star in the heavens would, if we could find out all about it, reveal far more than
all the astronomers that were ever on the earth have even conjectured. What we actually
learn about the great majority of stars is only information of the most meagre description. We
see that the star is a little point of light, and we see nothing more.
In the great review which Herschel undertook he doubtless examined hundreds, or perhaps
thousands of stars, allowing them to pass away without note or comment. But on an ever-
memorable night in March, 1782, it happened that he was pursuing his task among the stars
in the Constellation of Gemini. Doubtless, on that night, as on so many other nights, one star
after another was looked at only to be dismissed, as not requiring further attention. On the
evening in question, however, one star was noticed which, to Herschel's acute vision seemed
different from the stars which in so many thousands are strewn over the sky. A star properly
so called appears merely as a little point of light, which no increase of magnifying power will
ever exhibit with a true disc. But there was something in the star-like object which Herschel
saw that immediately arrested his attention and made him apply to it a higher magnifying
power. This at once disclosed the fact that the object possessed a disc, that is, a definite,
measurable size, and that it was thus totally different from any one of the hundreds and
thousands of stars which exist elsewhere in space. Indeed, we may say at once that this little
object was not a star at all; it was a planet. That such was its true nature was confirmed, after
a little further observation, by perceiving that the body was shifting its place on the heavens
relatively to the stars. The organist at the Octagon Chapel at Bath had, therefore, discovered a
new planet with his home-made telescope.
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I can imagine some one will say, "Oh, there was nothing so wonderful in that; are not planets
always being discovered? Has not M. Palisa, for instance discovered about eighty of such
objects, and are there not hundreds of them known nowadays?" This is, to a certain extent,
quite true. I have not the least desire to detract from the credit of those industrious and sharp-
sighted astronomers who have in modern days brought so many of these little objects within
our cognisance. I think, however, it must be admitted that such discoveries have a totally
different importance in the history of science from that which belongs to the peerless
achievement of Herschel. In the first place, it must be observed that the minor planets now
brought to light are so minute that if a score of them were rolled to together into one lump it
would not be one-thousandth part of the size of the grand planet discovered by Herschel. This
is, nevertheless, not the most important point. What marks Herschel's achievement as one of
the great epochs in the history of astronomy is the fact that the detection of Uranus was the
very first recorded occasion of the discovery of any planet whatever.
For uncounted ages those who watched the skies had been aware of the existence of the five
old planets-Jupiter, Mercury, Saturn, Venus, and Mars. It never seems to have occurred to any
of the ancient philosophers that there could be other similar objects as yet undetected over
and above the well-known five. Great then was the astonishment of the scientific world when
the Bath organist announced his discovery that the five planets which had been known from
all antiquity must now admit the company of a sixth. And this sixth planet was, indeed, worthy
on every ground to be received into the ranks of the five glorious bodies of antiquity. It was,
no doubt, not so large as Saturn, it was certainly very much less than Jupiter; on the other
hand, the new body was very much larger than Mercury, than Venus, or than Mars, and the
earth itself seemed quite an insignificant object in comparison with this newly added member
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