_THE TELESCOPE AND ITS REVELATIONS._
Term of Professorship at Padua renewed.—Astronomy.—A New
Star.—The Telescope.—Galileo not the Inventor.—Visit to Venice
to exhibit it.—Telescopic Discoveries.—Jupiter’s Moons.—Request
of Henry IV.—“Sidereus Nuncius.”—The Storm it raised.—Magini’s
attack on Galileo.—The Ring of Saturn.—An Anagram.—Opposition
of the Aristotelian School.—Letter to Kepler.
The first six years of Galileo’s professorship at Padua had passed
away, but the senate were eager to retain so bright a light for their
University, and prolonged the appointment of the professor, whose renown
was now great, for another six years, with a considerable increase of
salary.[35]
As we have seen, he had for a long time renounced the prevailing views
about the universe; but up to this time he had discussed only physical
mathematical questions with the Peripatetic school, the subject of
astronomy had not been mooted. But the sudden appearance of a new
star in the constellation of Serpentarius, in October, 1604, which,
after exhibiting various colours for a year and a half, as suddenly
disappeared, induced him openly to attack one of the Aristotelian
doctrines hitherto held most sacred, that of the unchangeableness of the
heavens. Galileo demonstrated, in three lectures to a numerous audience,
that this star was neither a mere meteor, nor yet a heavenly body which
had before existed but had only now been observed, but a body which had
recently appeared and had again vanished.[36] The subject, though not
immediately connected with the Copernican question, was an important
step taken on the dangerous and rarely trodden path of knowledge of
nature, uninfluenced by dogmatism or petrified professorial wisdom.
This inviolability of the vault of heaven was also conditioned by the
prevailing views of the universe. What wonder then that most of the
professors who had grown grey in the Aristotelian doctrine (Cremonio for
instance, Coressio, Lodovico delle Colombo, and Balthasar Capra) were
incensed at these opinions of Galileo, so opposed to all their scientific
prepossessions, and vehemently controverted them.
The spark, however, which was to set fire to the abundant inflammable
material, and to turn the scientific and religious world, in which doubt
had before been glimmering, into a veritable volcano, the spark which
kindled Galileo’s genius and made him for a long time the centre of that
period of storm and stress, was the discovery of the telescope.
We will not claim for Galileo, as many of his biographers have
erroneously done, priority in the construction of the telescope. We rely
far more on Galileo’s own statements than on those of his eulogists, who
aim at effect. Galileo relates with perfect simplicity at the beginning
of the “Sidereus Nuncius,” published at Venice in 1610, that he had heard
about ten months ago that an instrument had been made by a Dutchman,
by means of which distant objects were brought nearer and could be
seen very plainly. The confirmation of the report by one of his former
pupils, a French nobleman, Jean Badovere of Paris, had induced him to
reflect upon the means by which such an effect could be produced. By
the laws of refraction he soon attained his end. With two glasses fixed
at the ends of a leaden tube, both having one side flat and the other
side of the one being concave and of the other convex, his primitive
telescope, which made objects appear three times nearer and nine times
larger, was constructed. But now, having “spared neither expense nor
labour,” he had got so far as to construct an instrument which magnified
an object nearly a thousand times, and brought it more than thirty
times nearer.[37] Although, therefore, it is clear from this that the
first idea of the telescope does not belong to Galileo, it is equally
clear that he found out how to construct it from his own reflection and
experiments. Undoubtedly also the merit of having made great improvements
in it belongs to him, which is shown by the fact that at that time,
and long afterwards, his telescopes were the most sought after, and
that he received numerous orders for them from learned men, princes and
governments in distant lands, Holland, the birthplace of the telescope,
not excepted.[38] But the idea which first gave to the instrument
its scientific importance, the application of it to astronomical
observations, belongs not to the original inventor but to the genius of
Galileo. This alone would have made his name immortal.[39]
A few days after he had constructed his instrument, imperfect as it
doubtless was, he hastened with it to Venice, having received an
invitation, to exhibit it to the doge and senate, for he at once
recognised its importance, if not to the full extent. We will now let
Galileo speak for himself in a letter which he wrote from Venice to his
brother-in-law, Benedetto Landucci:—
“You must know then that about two months ago a report was
spread here that in Flanders a spy-glass had been presented to
Prince Maurice, so ingeniously constructed that it made the
most distant objects appear quite near, so that a man could
be seen quite plainly at a distance of two _miglia_. This
result seemed to me so extraordinary that it set me thinking;
and as it appeared to me that it depended upon the theory of
perspective, I reflected on the manner of constructing it,
in which I was at length so entirely successful that I made
a spy-glass which far surpasses the report of the Flanders
one. As the news had reached Venice that I had made such an
instrument, six days ago I was summoned before their highnesses
the signoria, and exhibited it to them, to the astonishment of
the whole senate. Many noblemen and senators, although of a
great age, mounted the steps of the highest church towers at
Venice, in order to see sails and shipping that were so far off
that it was two hours before they were seen steering full sail
into the harbour without my spy-glass, for the effect of my
instrument is such that it makes an object fifty _miglia_ off
appear as large and near as if it were only five.”[40]
Galileo further relates in the same letter that he had presented one of
his instruments to the senate, in return for which his professorship at
Padua had been conferred on him for life, with an increase of salary to
one thousand florins.[41]
On his return to Padua he became eagerly engrossed in telescopic
observation of the heavens. The astonishing and sublime discoveries
which were disclosed to him must in any case have possessed the deepest
interest for the philosopher who was continually seeking to solve
nature’s problems, and were all the more so, since they contributed
materially to confirm the Copernican theory.
His observations were first directed to the moon, and he discovered that
its surface was mountainous, which showed at all events that the earth’s
satellite was something like the earth itself, and therefore by no means
restored it to the aristocratic position in the universe from which it
had been displaced by Copernicus. The milky way, as seen through the
telescope, revealed an immense number of small stars. In Orion, instead
of the seven heavenly bodies already known, five hundred new stars were
seen; the number of the Pleiades, which had been fixed at seven, rose to
thirty-six; the planets showed themselves as disks, while the fixed stars
appeared as before, as mere bright specks in the firmament.
But the indefatigable observer’s far most important discovery, in its
bearing on the Copernican theory, was that of the moons of Jupiter,
in January 1610. As they exhibited motions precisely similar to those
which Copernicus had assumed for the whole solar system, they strongly
fortified his theory. It was placed beyond all doubt that our planet
was not the centre of all the heavenly bodies, since Jupiter’s moons
revolved round him. The latter was brought, so to speak, by the discovery
of his attendants, into relations with the earth which, considering
the prevailing views, were humiliating enough, and the more so since
Jupiter had four satellites while the earth had only one. There remained,
however, the consoling assurance that he and they revolved round our
abode!
In honour of the reigning house of his native country, and as an
acknowledgment of favours received from it (for since the accession of
Cosmo II.[42] Galileo had been in high favour), he called Jupiter’s moons
“Medicean stars.” The urgent solicitude of the French court to gain, by
Galileo’s aid, a permanent place on the chart of the heavens, is very
amusing. Thus, on 20th April, 1610, he received a pressing request, “in
case he discovered any other fine star, to call it after the great star
of France, Henry IV., then reigning, the most brilliant in the whole
universe, and to give it his proper name of Henry rather than that of the
family name of Bourbon.” Galileo communicated this flattering request, as
he seems to have considered it, with much satisfaction to the secretary
of the Tuscan court, Vincenzo Giugni, in a letter from Padua, on 25th
June, 1610,[43] as an evidence of the great importance attached to his
telescopic discoveries. He added that he did not expect to find any more
planets, as he had already made many very close observations.
Galileo published by degrees all the discoveries he had made at Padua,
of which we have only noticed the most important, in the work before
mentioned, the “Sidereus Nuncius”; it was dedicated to the Grand Duke,
Cosmo II., and the first edition appeared at Venice, in March, 1610.
Although the unexpected discoveries which Galileo had made with his
telescope had confirmed his opinion that the system of Copernicus was
the only one consistent with the facts of nature, had indeed made it his
absolute conviction, he had not yet ventured to defend it in his works.
He contented himself with stating bare facts, without showing their
relation to the ideas of Copernicus, leaving this to the learning and
insight of the reader. Moreover, the logical inferences from Jupiter’s
moons must surely stare every thoughtful man in the face, and so indeed
they did in a way very unwelcome to the scientific conservatives.
The storm raised by Galileo’s latest announcements was tremendous. People
heard with amazement the extraordinary things which the new invention had
brought to light, and paid a just tribute of admiration to the man to
whose labours it was due. But these discoveries were so directly opposed
to the traditional natural philosophy, still regarded as the highest
wisdom, that the “Sidereus Nuncius” had met with many opponents. It must
however be borne in mind that at the time of its first publication very
few of the learned were in a position to convince themselves with their
own eyes of the correctness of the appearances seen with the telescope,
simply because they had not the instrument at hand. From this cause, even
Kepler did not see the satellites of Jupiter till 30th August, 1610. But
men so free from jealousy and prejudice as Kepler (who, on reading the
“Sidereus Nuncius,” at once recognised the truth of the discoveries, and
said with enthusiasm that “Galileo had in this book given evidence of the
divinity of his genius”[44]), have at all times been rare.
At first, therefore, the majority of the learned world shook their heads
incredulously about the phenomena announced by the “Nuncius,” especially
in Italy, where envy lent its aid to bring an armed opposition into the
field. Little did it at first avail that Kepler, renowned as the first
astronomer in Germany, was on the side of the “Sidereus Nuncius”; for
in May of the same year he had a reprint of the work issued at Prague,
with an introduction in which he expressed his entire conviction of the
truth of the telescopic discoveries made known by it, and answered all
objections.[45] In vain. These new discoveries were too revolutionary
to be believed. Even upright and estimable scientific men, like Welser
in Augsburg, and Clavius at Rome, did not give credit to Galileo’s
statements until they learnt better by their own observations. The
latter, who was the first mathematician in Rome in his day, even said
“he laughed at the pretended satellites of Jupiter; you must construct a
telescope which would first make them and then show them.” Let Galileo
hold his own opinions, and he (Clavius) would hold his.[46]
But the leader of an unworthy agitation in Italy against Galileo was
a man who assumed this attitude from very different motives from the
sacred service of science. This was the well-known Professor Magini,
astronomer at the university of Bologna, who, next to Galileo, enjoyed
the highest reputation for learning in Italy. He could not brook that
his famous countryman should all at once obtain the highest fame with
seven-league boots, leaving a pigmy like himself far behind, by means of
the discoveries made known in his “Sidereus Nuncius.” He must not only be
refuted, the refutation must be circulated as widely as possible. But
the most repulsive feature in Magini’s conduct towards Galileo is his
double-facedness. He never openly ventured with any work into the arena
himself, but incited others all the more from behind concealment.[47]
Even if we do not, with Martin Hasdal and Alexander Sertini, accuse him
of being exactly the instigator of the famous libel “Peregrinatio contra
Nuncium Sidereum,” published by his assistant, Martin Horky, against
Galileo in 1610, which excited the indignation of all the right-minded
learned world, we cannot acquit him of complicity with him, and of
having had a hand, more or less, in that pamphlet. The suspicion is
strongly confirmed by the ostentation with which Magini, when told of
the publication of the “Peregrinatio,” drove the author, with disgust
and ridicule, out of his house, and took occasion to assert on all hands
that he had nothing whatever to do with the shameful act of his famulus,
an assertion in strange contradiction with the excuse afterwards made
by Horky to Kepler.[48] By Kepler’s advice Galileo did not do him the
honour of answering. The task was undertaken by Wedderburn, a Scotchman,
formerly a pupil of Galileo’s, and Antonio Roffeni, professor of
philosophy at the university of Bologna; the former at Padua during the
same year, the latter at Bologna in 1611.[49]
Meanwhile, in July, 1610, Galileo had observed a new appearance in the
heavens by means of his telescope, the ring of Saturn. In consequence,
however, of the imperfection of the instrument, it did not appear like a
ring, but Saturn looked like a triple star. Galileo, who on the one hand
did not wish to make the new discovery public until he had sufficiently
observed it, yet feared on the other that some one might claim priority,
at once communicated it in a letter from Padua, 30th July, 1610,[50] to
his influential friend Belisario Vinta, chief secretary of state to Cosmo
II., but urgently begged him to keep it a secret. But even this did not
seem sufficient to secure his right to the first observation of Saturn,
so he announced it to his friends in the following absurd anagram:—
SMAJSMRMJLMEPOETALEVNJPVNENVGTTAVJRAS.
Kepler puzzled for a long time over this enigma, and at last only made
out the barbaric line, “Salve umbistineum geminatum Martia proles,” which
he incorrectly applied to the planet Mars. At length, after repeated
requests, and after Julian de’ Medici, Tuscan ambassador at the Imperial
court, had been charged by the Emperor to ask for a solution, he complied
with the illustrious wish, and in a letter to Julian of 13th November,
1610,[51] gave the following startling explanation:—
Altissimum Planetam tergeminum observavi.
The learned and semi-learned world of Italy had not yet had time to
become reconciled to the surprising discoveries announced in the
“Sidereus Nuncius” of March in the same year, when the asserted triple
nature of Saturn contravened the prevailing idea that there was nothing
new to be discovered in the heavens. The recognition of Galileo’s
telescopic discoveries made way very slowly. From the first he spared
no pains in popularising them. He did this repeatedly in public
lectures, and with so much success that he could write to Vinta: “even
the most exalted personages, who have been most vehement in attacking
my doctrines, at length gave up the game for lost, and acknowledged,
_coram populo_, that they were not only convinced but ready to defend
them against those philosophers and mathematicians who ventured to attack
them.”[52]
But it was only at the University of Padua that Galileo could report
such rapid progress; and until the Maginis, Clavios, and others were
convinced by their own eyes, and confirmed to their own party the
truth of Galileo’s disclosures, he had to sustain a hard struggle with
incredulity, malice, and peripatetic fanaticism. Some rabid Aristotelians
went so far as to say that Galileo’s telescope was so constructed as to
show things that did not exist! Nor did it mend the matter much when
he offered 10,000 scudi to any one who should construct so cunning an
instrument.[53] Others resolutely refused even to look through the
telescope, giving it as their firm conviction that they would not be
able to see appearances which Aristotle had not said a word about in
all his books! The answer that Aristotle was not acquainted with the
telescope, and could not have known anything of telescopic appearances,
rebounded without effect from the petrified infallibility of Aristotelian
wisdom. Nor must it be supposed that these short-sighted conservatives
only numbered a few would-be _savans_ of the Peripatetic school; on the
contrary, celebrities like Cesare Cremonino da Cento, and Julius Libri,
denied Galileo’s discoveries _a priori_.[54] When Libri died in December,
1610, without having been willing to look through a telescope, and
protesting against Galileo’s “absurdities,” Galileo wrote in a letter of
17th December that this rigid opponent of his “absurdities,” as he was
never willing to look at them from earth, might perhaps see them on his
way to heaven![55]
Some passages from a letter of Galileo’s to Kepler, of 19th August,
1610, will best show how some of these men of science turned away with a
righteous awe from the inconvenient recognition of the truth. Galileo
writes among other things:—
“You are the first and almost the only person who, even after
but a cursory investigation, has, such is your openness of mind
and lofty genius, given entire credit to my statements.... We
will not trouble ourselves about the abuse of the multitude,
for against Jupiter even giants, to say nothing of pigmies,
fight in vain. Let Jupiter stand in the heavens, and let the
sycophants bark at him as they will.... In Pisa, Florence,
Bologna, Venice, and Padua many have seen the planets; but
all are silent on the subject and undecided, for the greater
number recognise neither Jupiter nor Mars and scarcely the
moon as planets. At Venice one man spoke against me, boasting
that he knew for certain that my satellites of Jupiter, which
he had several times observed, were not planets because they
were always to be seen with Jupiter, and either all or some
of them, now followed and now preceded him. What is to be
done? Shall we side with Democritus or Heraclitus? I think, my
Kepler, we will laugh at the extraordinary stupidity of the
multitude. What do you say to the leading philosophers of the
faculty here, to whom I have offered a thousand times of my own
accord to show my studies, but who with the lazy obstinacy of
a serpent who has eaten his fill have never consented to look
at planets, nor moon, nor telescope? Verily, just as serpents
close their ears, so do these men close their eyes to the light
of truth. These are great matters; yet they do not occasion me
any surprise. People of this sort think that philosophy is a
kind of book like the Æneid or the Odyssey, and that the truth
is to be sought, not in the universe, not in nature, but (I
use their own words) _by comparing texts_! How you would laugh
if you heard what things the first philosopher of the faculty
at Pisa brought against me in the presence of the Grand Duke,
for he tried, now with logical arguments, now with magical
adjurations, to tear down and argue the new planets out of
heaven.”[56]