Great Astronomers by Robert Stawell Ball (uplifting novels .txt) 📕
Ptolemy commences with laying down the undoubted truth that the shape of the earth is globular. The proofs which he gives of this fundamental fact are quite satisfactory; they are indeed the same proofs as we give today. There is, first of all, the well-known circumstance of which our books on geography remind us, that when an object is viewed at a distance across the sea, the lower part of the object appears cut off by the interposing curved mass of water.
The sagacity of Ptolemy enabled him to adduce another argument, which, though not quite so obvious as that just mentioned, demonstrates the curvature of the earth in a very impressive manner to anyone who will take the trouble to understand it. Ptolemy mentions that travellers who went to the south
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“If, then, it be painfully evident to both, that under such
circumstances there CANNOT (whatever we may both DESIRE) be NOW in
the nature of things, or of minds, the same degree of INTIMACY
between us as of old; since we could no longer TALK with the same
degree of unreserve on every subject which happened to present
itself, but MUST, from the simplest instincts of courtesy, be each
on his guard not to say what might be offensive, or, at least,
painful to the other; yet WE were ONCE so intimate, an retain
still, and, as I trust, shall always retain, so much of regard and
esteem and appreciation for each other, made tender by so
many associations of my early youth and your boyhood, which can
never be forgotten by either of us, that (as times go) TWO OR
THREE VERY RESPECTABLE FRIENDSHIPS might easily be carved out from
the fragments of our former and ever-to-be-remembered INTIMACY.
It would be no exaggeration to quote the words: ‘Heu! quanto minus
est cum reliquis versari, quam tui meminisse!’”
In 1858 a correspondence on the subject of Quaternions; commenced
between Professor Tait and Sir William Hamilton. It was
particularly gratifying to the discoverer that so competent a
mathematician as Professor Tait should have made himself
acquainted with the new calculus. It is, of course, well known
that Professor Tait subsequently brought out a most valuable
elementary treatise on Quaternions, to which those who are anxious
to become acquainted with the subject will often turn in
preference to the tremendous work of Hamilton.
In the year 1861 gratifying information came to hand of the
progress which the study of Quaternions was making abroad.
Especially did the subject attract the attention of that
accomplished mathematician, Moebius, who had already in his
“Barycentrische Calculus” been led to conceptions which bore
more affinity to Quaternions than could be found in the writings
of any other mathematician. Such notices of his work were
always pleasing to Hamilton, and they served, perhaps, as
incentives to that still closer and more engrossing labour by
which he became more and more absorbed. During the last few
years of his life he was observed to be even more of a
recluse than he had hitherto been. His powers of long and
continuous study seemed to grow with advancing years, and his
intervals of relaxation, such as they were, became more brief
and more infrequent.
It was not unusual for him to work for twelve hours at a stretch.
The dawn would frequently surprise him as he looked up to snuff
his candles after a night of fascinating labour at original
research. Regularity in habits was impossible to a student who
had prolonged fits of what he called his mathematical trances.
Hours for rest and hours for meals could only be snatched in the
occasional the lucid intervals between one attack of Quaternions
and the next. When hungry, he would go to see whether any thing
could be found on the sideboard; when thirsty, he would visit the
locker, and the one blemish in the man’s personal character is
that these latter visits were sometimes paid too often.
As an example of one of Hamilton’s rare diversions from the all-absorbing pursuit of Quaternions, we find that he was seized with
curiosity to calculate back to the date of the Hegira, which he
found on the 15th July, 622. He speaks of the satisfaction with
which he ascertained subsequently that Herschel had assigned
precisely the same date. Metaphysics remained also, as it had
ever been, a favourite subject of Hamilton’s readings and
meditations and of correspondence with his friends. He wrote a
very long letter to Dr. Ingleby on the subject of his
“Introduction to Metaphysics.” In it Hamilton alludes, as he has
done also in other places, to a peculiarity of his own vision. It
was habitual to him, by some defect in the correlation of his
eyes, to see always a distinct image with each; in fact, he speaks
of the remarkable effect which the use of a good stereoscope had
on his sensations of vision. It was then, for the first time,
that he realised how the two images which he had always seen
hitherto would, under normal circumstances, be blended into one.
He cites this fact as bearing on the phenomena of binocular
vision, and he draws from it the inference that the necessity of
binocular vision for the correct appreciation of distance is
unfounded. “I am quite sure,” he says, “that I SEE DISTANCE with
EACH EYE SEPARATELY.”
The commencement of 1865, the last year of his life saw Hamilton
as diligent as ever, and corresponding with Salmon and Cayley. On
April 26th he writes to a friend to say, that his health has not
been good for years past, and that so much work has injured his
constitution; and he adds, that it is not conducive to good
spirits to find that he is accumulating another heavy bill with
the printer for the publication of the “Elements.” This was,
indeed, up to the day of his death, a cause for serious anxiety.
It may, however, be mentioned that the whole cost, which amounted
to nearly 500 pounds, was, like that of the previous volume,
ultimately borne by the College. Contrary to anticipation, the
enterprise, even in a pecuniary sense, cannot have been a very
unprofitable one. The whole edition has long been out of print,
and as much as 5 pounds has since been paid for a single copy.
It was on the 9th of May, 1865, that Hamilton was in Dublin for
the last time. A few days later he had a violent attack of gout,
and on the 4th of June he became alarmingly ill, and on the next
day had an attack of epileptic convulsions. However, he slightly
rallied, so that before the end of the month he was again at work
at the “Elements.” A gratifying incident brightened some of the
last days of his life. The National Academy of Science in America
had then been just formed. A list of foreign Associates had to be
chosen from the whole world, and a discussion took place as to
what name should be placed first on the list. Hamilton was
informed by private communication that this great distinction was
awarded to him by a majority of two-thirds.
In August he was still at work on the table of contents of the
“Elements,” and one of his very latest efforts was his letter to
Mr. Gould, in America, communicating his acknowledgements of the
honour which had been just conferred upon him by the National
Academy. On the 2nd of September Mr. Graves went to the
observatory, in response to a summons, and the great
mathematician at once admitted to his friend that he felt the end
was approaching. He mentioned that he had found in the 145th
Psalm a wonderfully suitable expression of his thoughts and
feelings, and he wished to testify his faith and thankfulness as a
Christian by partaking of the Lord’s Supper. He died at half-past
two on the afternoon of the 2nd of September, 1865, aged sixty
years and one month. He was buried in Mount Jerome Cemetery on
the 7th of September.
Many were the letters and other more public manifestations of the
feelings awakened by Hamilton’s death. Sir John Herschel wrote to
the widow:—
“Permit me only to add that among the many scientific friends whom
time has deprived me of, there has been none whom I more deeply
lament, not only for his splendid talents, but for the excellence
of his disposition and the perfect simplicity of his manners—so
great, and yet devoid of pretensions.”
De Morgan, his old mathematical crony, as Hamilton affectionately
styled him, also wrote to Lady Hamilton:—
“I have called him one of my dearest friends, and most truly; for
I know not how much longer than twenty-five years we have been in
intimate correspondence, of most friendly agreement or
disagreement, of most cordial interest in each other. And yet we
did not know each other’s faces. I met him about 1830 at
Babbage’s breakfast table, and there for the only time in our
lives we conversed. I saw him, a long way off, at the dinner
given to Herschel (about 1838) on his return from the Cape and
there we were not near enough, nor on that crowded day could we
get near enough, to
exchange a word. And this is all I ever saw, and, so it has
pleased God, all I shall see in this world of a man whose friendly
communications were among my greatest social enjoyments, and
greatest intellectual treats.”
There is a very interesting memoir of Hamilton written by De
Morgan, in the “Gentleman’s Magazine” for 1866, in which he produces
an excellent sketch of his friend, illustrated by personal
reminiscences and anecdotes. He alludes, among other things, to
the picturesque confusion of the papers in his study. There was
some sort of order in the mass, discernible however, by Hamilton
alone, and any invasion of the domestics, with a view to tidying
up, would throw the mathematician as we are informed, into “a good
honest thundering passion.”
Hardly any two men, who were both powerful mathematicians, could
have been more dissimilar in every other respect than were
Hamilton and De Morgan. The highly poetical temperament of
Hamilton was remarkably contrasted with the practical realism of
De Morgan. Hamilton sends sonnets to his friend, who replies by
giving the poet advice about making his will. The metaphysical
subtleties, with which Hamilton often filled his sheets, did not
seem to have the same attraction for De Morgan that he found in
battles about the quantification of the Predicate. De Morgan was
exquisitely witty, and though his jokes were always appreciated by
his correspondent, yet Hamilton seldom ventured on anything of the
same kind in reply; indeed his rare attempts at humour only
produced results of the most ponderous description. But never
were two scientific correspondents more perfectly in sympathy with
each other. Hamilton’s work on Quaternions, his labours in
Dynamics, his literary tastes, his metaphysics, and his poetry,
were all heartily welcomed by his friend, whose letters in reply
invariably evince the kindliest interest in all Hamilton’s
concerns. In a similar way De Morgan’s letters to Hamilton always
met with a heartfelt response.
Alike for the memory of Hamilton, for the credit of his
University, and for the benefit of science, let us hope that a
collected edition of his works will ere long appear—a collection
which shall show those early achievements in splendid
optical theory, those achievements of his more mature powers which
made him the Lagrange of his country, and finally those creations
of the Quaternion Calculus by which new capabilities have been
bestowed on the human intellect.
LE VERRIER.
The name of Le Verrier is one that goes down to fame on account of
very different discoveries from those which have given renown to
several of the other astronomers whom we have mentioned. We are
sometimes apt to identify the idea of an astronomer with that of a
man who looks through a telescope at the stars; but the word
astronomer has really much wider significance. No man who ever
lived has been more entitled to be designated an astronomer than
Le Verrier, and yet it is certain that he never made a telescopic
discovery of any kind. Indeed, so far as his scientific
achievements have been concerned, he might never have looked
through a telescope at all.
For the full interpretation of the movements of the heavenly
bodies, mathematical knowledge of the most advanced character is
demanded. The mathematician at the outset calls upon the
astronomer who uses the instruments in the observatory, to
ascertain for him at various times the exact positions occupied
by
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