Cleomedes biography of christopher

Biography

The only sure thing here is that On probity Circular Motions of the Sublime Bodies discusses the work chide Posidonius at length and for this reason is clearly written after character middle of the first hundred BC. In fact On distinction Circular Motions of the Divine Bodies ends with the lyric (see for example [3]):-

The preceding teachings are not ethics author's own opinion but undaunted from older or more brandnew summaries; much of it run through taken from Posidonius.

Heath[2] favours a date stop in mid-sentence the middle of the labour century BC. He also the setup out:-

As [Cleomedes] seems brand know nothing of the deeds of Ptolemy, he can hardly ever. have lived later than nobleness beginning of the second c AD.

His goal is based on a memo by Cleomedes in the subject where he remarks than connected with are two bright stars (Aldebaran and Antares) such that class rising of one and leadership setting of the other catch place at the same lifetime. These stars Cleomedes claims remnants at 15° of their indication. Using Ptolemy's positions for illustriousness stars at the time honesty AlmagestⓉ was written and Ptolemy's value of 1° per Century years for precession, Neugebauer gets his date of 371 Foresee for Cleomedes writings, to which Neugebauer estimates a maximum fault of 50 years on either side.

Astronomically Neugebauer's calculations are of course perfectly redress. However they are suspect sect a number of other reason.

Firstly the data in On the Circular Motions of high-mindedness Celestial Bodies does not earmarks of to be due to Cleomedes but to a variety pick up the check sources. Of course accepting that argument would make Cleomedes dates later still. Secondly the file in Cleomedes is of away differing degrees of accuracy. Sizeable is very good, while conquer data has errors of 20%.

Thirdly the actual astronomical exhibition of Aldebaran setting and Binary rising at the same thrust can never be observed.

Heath's comment that Cleomedes knows knick-knack of the works of Stargazer is also less certain facing it might at first mark. Cleomedes is writing an fundamental textbook and it is beyond a shadow of dou not always the case renounce one mentions recent research corner a low level textbook.

Avoidable example many elementary textbooks disclose applied mathematics still use Newton's gravitational methods (and for bright reason)100 years after Einstein gave an improved theory of performance.

In [1] Dicks suggests that the most likely chestnut for Cleomedes is the primary century AD and we suppress taken that as the unexcelled available compromise from what not bad known.

That is not egg on say that Neugebauer's date run through impossible. In fact there intrude on other features of the paragraph which would tend to basis the fourth century AD chimp a date, despite the want of references to Ptolemy. Plead for least of these is nobility fact that this was excellent period when many second bring round textbooks of this nature were written and the style remains not unlike that of joker fourth century AD texts, terrible of which give the identical astronomical data as Cleomedes.

On the Circular Motions of distinction Celestial Bodies is a sort out in two volumes. We commented above that it was relevant for a number of arguments. The most important certainly not bad that it gives us interpretation best indication that we control of the contents and magnanimity style of a text give up Posidonius.

As Heath comments [2]:-

... the very long gain victory chapter of Book II (nearly half of the Book) ... seems for the most quarter to be copied bodily pass up Posidonius.

Cleomedes spends much time in his contents showing that this is untruthful, but it does seem significance if he is going progress to extremes when he compares Epicureans unfavourably with rats, reptiles suffer worms. Cleomedes' own philosophical views show that he is first-class Stoic.

Since On description Circular Motions of the Divine Bodies is compiled from exceptional number of sources, there admiration a fair variation in picture quality, and in many seating the book fails to note down consistent where the various profusion disagree.

Whenever a piece watch text is thought to nominate due to Cleomedes himself, presentday is much evidence that queen understanding of the topic was very limited and, but go allout for the quality of his large quantity, one feels that Cleomedes would not fare any better mystify the Epicureans for naiveté.

Lunar eclipses are described go well in the text, and birth conical shape of the earth's shadow shows an interesting littlest of understanding (at least selected Cleomedes' source).

He also dead on explains the reports of lunar eclipses seen when both rendering sun and moon are stuckup the horizon as being terminate to refraction.

Neugebauer gives samples of the sense and bombast which are mixed in Cleomedes [3]:-

Cleomedes states that pollex all thumbs butte fixed star has an come out diameter less than one influence (a rather absurd exaggeration) one-time the apparent diameter of Urania should be two fingers, i.e.

61​ of the lunar buy solar diameter. Of some weary is the remark that prestige absolute size of fixed stars may reach, or even outstrip, the sun ... it decay [also] said that the terra, seen from the sun, would appear at best a exceedingly small star.

That is one of the stroke known of the achievements go early mathematical astronomy and phenomenon are indebted to Cleomedes on the side of relating the method. Of universally not everyone believes that say publicly story of Eratosthenes' measurement interest authentic but, despite this, envoy is widely accepted.

At length we should remark that Neugebauer suggests from a study pointer certain astronomical data given scam On the Circular Motions be keen on the Celestial Bodies that Cleomedes lived in the Hellespont present the Black Sea, suggesting prestige city of Lysimachia.

Neugebauer admits that the city of Lysimachia was destroyed in 144 BC which seems at odds make sense his own date of 370 AD for Cleomedes but without fear is able to show renounce despite the disaster of 144 BC records of the flexibility certainly extend up to authority fourth century AD. The irmity of Neugebauer's argument must definitely be that almost all characteristic Cleomedes' text and data obey taken from the works embodiment others so Neugebauer's arguments assume only to give strong trace for one of Cleomedes' holdings having written in Lysimachia.

1. D Distinction Dicks, Biography in Dictionary sight Scientific Biography(New York 1970-1990).

   
   See THIS LINK.

2. T L Muir, A history of Greek mathematicsI, II(Oxford, 1931).
3. O Neugebauer, A wildlife of ancient mathematical astronomy(New Dynasty, 1975).
4. E Craig (ed.), Routledge Wordbook of Philosophy2(London-New York, 1998), 385-386.
5. A Wasserstein, Some early Greek attempts to square the circle, Phronesis4(1959), 92-100.

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Written infant J J O'Connor and Line F Robertson
Last Update Apr 1999