User talk:David J Wilson/Ball's Great Astronomers

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[edit] Historical errors in Robert Stawell Ball's Great Astronomers

• After giving an account of Ptolemy's arguments for the roundness of the Earth, Ball writes:

"... it followed that the earth, instead of being the flat plain, girdled with an illimitable ocean, as was generally supposed, must be in reality globular. ..." (italics mine)

That the earth was "generally supposed" to be flat at the time of Ptolemy is poppycock. Even the most trenchant proponents of the conflict thesis, such as Andrew Dickson White and John William Draper, acknowledge that the proper shape of the earth was reasonably well known by that time (before it was supposedly suppressed by the Church during the so-called Dark Ages.^[1]).

• Further on, concerning Ptolemy's exposition of the shape of the Earth, Ball writes:

"The perception of this sublime truth marks a notable epoch in the history of the gradual development of the human intellect. No doubt, other philosophers, in groping after knowledge, may have set forth certain assertions that are more or less equivalent to this fundamental truth. It is to Ptolemy we must give credit, however, not only for announcing this doctrine, but for demonstrating it by clear and logical argument."

Really? What about Aristotle's arguments in his widely known work De Caelo some 450-500 years earlier? What about Eratosthenes's measurement of the radius of the Earth (well-known, even in antiquity) some 350 or so years earlier?

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"The simplest observations, however, show that the movements of the planets cannot be explained in this simple fashion [i.e. by simple circular motion around the earth]. Here the geometrical genius of Ptolemy shone forth, and he devised a scheme by which the apparent wanderings of the planets could be accounted for without the introduction of aught save "perfect" movements."

Ball goes on to misattribute the invention of epicycle-deferent system to Ptolemy. In fact these devices had long been known by the time Ptolemy wrote the Almagest. Even Ptolemy himself, in the 12th book of the Almagest notes that "various mathematicians, including Apollonius of Perga" (ca. 262 BC-ca. 190 BC) had found that this system could be used to explain the retrograde motions of the outer planets. The invention of the epicycle-deferent system has more generally been credited to Apollonius.

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"The explanation of the movement of an outer planet like Mars could also be deduced from the joint effect of two perfect motions.

. . . .

"We are to suppose that at a point marked M there is a fictitious planet, which revolves around the earth uniformly, in a circle called the DEFERENT. This point M, which is thus animated by a perfect movement, is the centre of a circle which is carried onwards with M, and around the circumference of which Mars revolves uniformly. It is easy to show that the combined effect of these two perfect movements is to produce exactly that displacement of Mars in the heavens which observation discloses.

. . . .

"The other outer planets with which Ptolemy was acquainted, namely, Jupiter and Saturn, had movements of the same general character as those of Mars. Ptolemy was equally successful in explaining the movements they performed by the supposition that each planet had perfect rotation in a circle of its own, which circle itself had perfect movement around the earth in the centre."

This is a misleading oversimplification. In Ptolemy's system the deferent was not centred on the earth. For the outer planets it was an eccentric circle—that is, one whose centre was offset from the centre of the earth. Also, the centre of an outer planet's epicycle did not move with uniform motion around the deferent, but in such a way that the angle it subtended at another point (called the equant), offset from the centre of the deferent, changed at a uniform rate. Far from being considered "perfect", this non-uniform motion about the deferent was considered a serious defect in Ptolemy's model by later astronomers.

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"It would appear that the young Nicolaus, for such was his Christian name, received his education at home until such time as he was deemed sufficiently advanced to be sent to the University at Cracow. The education that he there obtained must have been in those days of a very primitive description, but Copernicus seems to have availed himself of it to the utmost. He devoted himself more particularly to the study of medicine, with the view of adopting its practice as the profession of his life."

According to Angus Armitage's biography, Copernicus, the Founder of Modern Astronomy, Copernicus was sent to school in Torun and then in Wloclawek before he went to the University of Cracow. Even if one regards education at school in Torun as being "at home", one could hardly do the same for Wloclawek, which was some distance from Torun. And while one might argue that the education then available at the University of Cracow would have been "of a very primitive description" according to today's standards, Koyré says in The Astronomical Revolution that it "enjoyed a very high reputation at that time" and "it had become the most important university in the east, being justly famous as a centre of scientific and classical culture", and Armitage says that "a brilliant school of mathematics and astronomy had been built up" there by Albert Brudsewsky.

No other biography of Copernicus that I know of claims that he studied medicine while at Cracow. Michael Crowe (Theories of the World from Antiquity to the Copernican Revolution), J.L.E.Dreyer (A History of Astronomy from Thales to Kepler), and Armitage only state that he studied it much later at Padua, while Koyré says that he studied it at Bologna as well. Koyré also says "We have no information about the course of studies followed by Copernicus at Cracow".

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"Pythagoras, it appears, had indeed told his disciples that it was the sun, and not the earth, which was the centre of movement, ..."

The Pythagorean model of the universe did not place the sun at "the centre of movement".

•  

"Galileo was born at Pisa, on 18th February, 1564. He was the eldest son of Vincenzo de' Bonajuti de' Galilei, a Florentine noble."

No other biography of Galileo that I know of claims that his father was a "Florentine noble".

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"The youthful professor [Galileo] let fall from the overhanging top [of the leaning tower of Pisa] a large heavy body and a small light body simultaneously. According to Aristotle the large body ought to have reached the ground much sooner than the small one, but such was found not to be the case. In the sight of a large concourse of people the simple fact was demonstrated that the two bodies fell side by side, and reached the ground at the same time."

There is no first hand account by Galileo of this alleged event, nor any other contemporaneous account of it or reference to it. It is recounted by Vincenzio Viviani, Galileo's last pupil and amanuensis, in his hagiographical biography. All Most other biographies of Galileo that I have read consider Viviani's account to be unreliable (he apparently had Galileo performing the experiment in front of an assembly of colleagues, philosophers and all the students of the University). See Michael Sharratt's Galileo—Decisive Innovator, p.47, for example.

Supplementary note: Since writing this, I have since discovered that Stillman Drake, in Galileo at Work (pp.20, 415-416) is inclined to believe that some such demonstration by Galileo could very well have taken place.

—David Wilson (talk · cont) 03:39, 1 March 2008 (UTC)

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"Two daughters, Polissena and Virginia, and one son, Vincenzo, had been born to Galileo in Padua."

Galileo's daughters were called Livia (not Polissena) and Virginia.

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"The elder daughter Polissena, took the name of Sister Maria Celeste, while Virginia became Sister Arcangela."

It was Virginia who was the elder daughter and who became Sister Maria Celeste, and Livia who became Sister Arcangela.

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"On the death of Paul V. in 1623, Maffeo Barberini was elected Pope, as Urban VIII."

Pope Paul V died in 1621, not 1623, and was succeeded by Gregory XV, not Urban VIII. It was Gregory who died in 1623 and was succeeded by Urban.

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Formal leave for the publication of the Dialogue was then given to Galileo by the Inquisitor General, and it was accordingly sent to the press."

The leave for publication was granted by the Master of the Sacred Palace, then Father Niccolò Riccardi. Riccardi was not even a member of the Congregation of the Holy Office (aka the "Roman Inquisition"), let alone "Inquisitor General". Exactly what Ball meant by "Inquistior General" is anyone's guess. Unlike in the Spanish Inquisition the highest office in the Roman Inquisition (apart from that of the Pope himself) was not called Inquisitor General, but Commissary of the Holy Office. At the time in question the Commissary of the Holy Office was Father Vincenzo Maculano.

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'Riccardi, the Master of the Sacred Palace, having suddenly had some further misgivings, sent to Galileo for the manuscript while the work was at the printer's, in order that the doctrine it implied might be once again examined."

This never happened. Riccardi had demanded that during the printing of the Dialogue he was to be sent the entire manuscript page by page so he could check each one before it went to the printer. However, because of an outbreak of the plague, Galileo decided to have it printed in Florence rather than Rome and Riccardi relinquished responsiblity for checking the final draft to the Florentine Inquisitor.

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"But presently the Master of The Sacred Palace found reason to regret that he had given his consent to its appearance. He accordingly issued a peremptory order to sequestrate every copy in Italy."

While it is true that Riccardi "found reason to regret" his decision to grant an imprimatur to the Dialogue, Ball's account gives the impression that his change of mind was simply the result of further reflection on his own part, and that he issued the supposed subsequent sequestration order on his own initiative. In fact, the reason for his regret was that the Pope's anger on hearing (and perhaps seeing) what was in the Dialogue was directed partly at him. The order to halt the sales of the Dialogue was issued by Francesco Barberini, not Riccardi, and the order for its confiscation was issued by the Pope himself, at the end of Galileo's trial.

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"In his defence Galileo urged that he had already been acquitted in 1616 by Cardinal Bellarmine, when a charge of heresy was brought against him, and he contended that anything he might now have done, was no more than he had done on the preceding occasion, when the orthodoxy of his doctrines received solemn confirmation."

No such charge of heresy had been "brought against" Galileo in 1616 and nor did he say during his trial that it had, or that Bellarmine had "acquitted" him of this non-existent charge. Neither is it true that "the orthodoxy of his doctrines received solemn confirmation" in 1616 or that he contended that it had during his trial. What is true is that two complaints against Galileo were made to the Inquisition early in 1615. But the Inquisition eventually dismissed them without ever bringing any charges against him.

[edit] Footnotes