A history of Greek mathematics Vol.II from Aristarchus to Diophantus by Heath, Thomas Little, Sir, 1921
MACEDONIA is GREECE and will always be GREECE- (if they are desperate to steal a name, Monkeydonkeys suits them just fine) ΚΑΤΩ Η ΣΥΓΚΥΒΕΡΝΗΣΗ ΤΩΝ ΠΡΟΔΟΤΩΝ!!! ΦΕΚ,ΚΚΕ,ΚΝΕ,ΚΟΜΜΟΥΝΙΣΜΟΣ,ΣΥΡΙΖΑ,ΠΑΣΟΚ,ΝΕΑ ΔΗΜΟΚΡΑΤΙΑ,ΕΓΚΛΗΜΑΤΑ,ΔΑΠ-ΝΔΦΚ, MACEDONIA,ΣΥΜΜΟΡΙΤΟΠΟΛΕΜΟΣ,ΠΡΟΣΦΟΡΕΣ,ΥΠΟΥΡΓΕΙΟ,ΕΝΟΠΛΕΣ ΔΥΝΑΜΕΙΣ,ΣΤΡΑΤΟΣ, ΑΕΡΟΠΟΡΙΑ,ΑΣΤΥΝΟΜΙΑ,ΔΗΜΑΡΧΕΙΟ,ΝΟΜΑΡΧΙΑ,ΠΑΝΕΠΙΣΤΗΜΙΟ,ΛΟΓΟΤΕΧΝΙΑ,ΔΗΜΟΣ,LIFO,ΛΑΡΙΣΑ, ΠΕΡΙΦΕΡΕΙΑ,ΕΚΚΛΗΣΙΑ,ΟΝΝΕΔ,ΜΟΝΗ,ΠΑΤΡΙΑΡΧΕΙΟ,ΜΕΣΗ ΕΚΠΑΙΔΕΥΣΗ,ΙΑΤΡΙΚΗ,ΟΛΜΕ,ΑΕΚ,ΠΑΟΚ,ΦΙΛΟΛΟΓΙΚΑ,ΝΟΜΟΘΕΣΙΑ,ΔΙΚΗΓΟΡΙΚΟΣ,ΕΠΙΠΛΟ, ΣΥΜΒΟΛΑΙΟΓΡΑΦΙΚΟΣ,ΕΛΛΗΝΙΚΑ,ΜΑΘΗΜΑΤΙΚΑ,ΝΕΟΛΑΙΑ,ΟΙΚΟΝΟΜΙΚΑ,ΙΣΤΟΡΙΑ,ΙΣΤΟΡΙΚΑ,ΑΥΓΗ,ΤΑ ΝΕΑ,ΕΘΝΟΣ,ΣΟΣΙΑΛΙΣΜΟΣ,LEFT,ΕΦΗΜΕΡΙΔΑ,ΚΟΚΚΙΝΟ,ATHENS VOICE,ΧΡΗΜΑ,ΟΙΚΟΝΟΜΙΑ,ΕΝΕΡΓΕΙΑ, ΡΑΤΣΙΣΜΟΣ,ΠΡΟΣΦΥΓΕΣ,GREECE,ΚΟΣΜΟΣ,ΜΑΓΕΙΡΙΚΗ,ΣΥΝΤΑΓΕΣ,ΕΛΛΗΝΙΣΜΟΣ,ΕΛΛΑΔΑ, ΕΜΦΥΛΙΟΣ,ΤΗΛΕΟΡΑΣΗ,ΕΓΚΥΚΛΙΟΣ,ΡΑΔΙΟΦΩΝΟ,ΓΥΜΝΑΣΤΙΚΗ,ΑΓΡΟΤΙΚΗ,ΟΛΥΜΠΙΑΚΟΣ, ΜΥΤΙΛΗΝΗ,ΧΙΟΣ,ΣΑΜΟΣ,ΠΑΤΡΙΔΑ,ΒΙΒΛΙΟ,ΕΡΕΥΝΑ,ΠΟΛΙΤΙΚΗ,ΚΥΝΗΓΕΤΙΚΑ,ΚΥΝΗΓΙ,ΘΡΙΛΕΡ, ΠΕΡΙΟΔΙΚΟ,ΤΕΥΧΟΣ,ΜΥΘΙΣΤΟΡΗΜΑ,ΑΔΩΝΙΣ ΓΕΩΡΓΙΑΔΗΣ,GEORGIADIS,ΦΑΝΤΑΣΤΙΚΕΣ ΙΣΤΟΡΙΕΣ, ΑΣΤΥΝΟΜΙΚΑ,ΦΙΛΟΣΟΦΙΚΗ,ΦΙΛΟΣΟΦΙΚΑ,ΙΚΕΑ,ΜΑΚΕΔΟΝΙΑ,ΑΤΤΙΚΗ,ΘΡΑΚΗ,ΘΕΣΣΑΛΟΝΙΚΗ,ΠΑΤΡΑ, ΙΟΝΙΟ,ΚΕΡΚΥΡΑ,ΚΩΣ,ΡΟΔΟΣ,ΚΑΒΑΛΑ,ΜΟΔΑ,ΔΡΑΜΑ,ΣΕΡΡΕΣ,ΕΥΡΥΤΑΝΙΑ,ΠΑΡΓΑ,ΚΕΦΑΛΟΝΙΑ, ΙΩΑΝΝΙΝΑ,ΛΕΥΚΑΔΑ,ΣΠΑΡΤΗ,ΠΑΞΟΙ
MACEDONIA is GREECE and will always be GREECE- (if they are desperate to steal a name, Monkeydonkeys suits them just fine)
ΚΑΤΩ Η ΣΥΓΚΥΒΕΡΝΗΣΗ ΤΩΝ ΠΡΟΔΟΤΩΝ!!!
ΦΕΚ,ΚΚΕ,ΚΝΕ,ΚΟΜΜΟΥΝΙΣΜΟΣ,ΣΥΡΙΖΑ,ΠΑΣΟΚ,ΝΕΑ ΔΗΜΟΚΡΑΤΙΑ,ΕΓΚΛΗΜΑΤΑ,ΔΑΠ-ΝΔΦΚ, MACEDONIA,ΣΥΜΜΟΡΙΤΟΠΟΛΕΜΟΣ,ΠΡΟΣΦΟΡΕΣ,ΥΠΟΥΡΓΕΙΟ,ΕΝΟΠΛΕΣ ΔΥΝΑΜΕΙΣ,ΣΤΡΑΤΟΣ, ΑΕΡΟΠΟΡΙΑ,ΑΣΤΥΝΟΜΙΑ,ΔΗΜΑΡΧΕΙΟ,ΝΟΜΑΡΧΙΑ,ΠΑΝΕΠΙΣΤΗΜΙΟ,ΛΟΓΟΤΕΧΝΙΑ,ΔΗΜΟΣ,LIFO,ΛΑΡΙΣΑ, ΠΕΡΙΦΕΡΕΙΑ,ΕΚΚΛΗΣΙΑ,ΟΝΝΕΔ,ΜΟΝΗ,ΠΑΤΡΙΑΡΧΕΙΟ,ΜΕΣΗ ΕΚΠΑΙΔΕΥΣΗ,ΙΑΤΡΙΚΗ,ΟΛΜΕ,ΑΕΚ,ΠΑΟΚ,ΦΙΛΟΛΟΓΙΚΑ,ΝΟΜΟΘΕΣΙΑ,ΔΙΚΗΓΟΡΙΚΟΣ,ΕΠΙΠΛΟ, ΣΥΜΒΟΛΑΙΟΓΡΑΦΙΚΟΣ,ΕΛΛΗΝΙΚΑ,ΜΑΘΗΜΑΤΙΚΑ,ΝΕΟΛΑΙΑ,ΟΙΚΟΝΟΜΙΚΑ,ΙΣΤΟΡΙΑ,ΙΣΤΟΡΙΚΑ,ΑΥΓΗ,ΤΑ ΝΕΑ,ΕΘΝΟΣ,ΣΟΣΙΑΛΙΣΜΟΣ,LEFT,ΕΦΗΜΕΡΙΔΑ,ΚΟΚΚΙΝΟ,ATHENS VOICE,ΧΡΗΜΑ,ΟΙΚΟΝΟΜΙΑ,ΕΝΕΡΓΕΙΑ, ΡΑΤΣΙΣΜΟΣ,ΠΡΟΣΦΥΓΕΣ,GREECE,ΚΟΣΜΟΣ,ΜΑΓΕΙΡΙΚΗ,ΣΥΝΤΑΓΕΣ,ΕΛΛΗΝΙΣΜΟΣ,ΕΛΛΑΔΑ, ΕΜΦΥΛΙΟΣ,ΤΗΛΕΟΡΑΣΗ,ΕΓΚΥΚΛΙΟΣ,ΡΑΔΙΟΦΩΝΟ,ΓΥΜΝΑΣΤΙΚΗ,ΑΓΡΟΤΙΚΗ,ΟΛΥΜΠΙΑΚΟΣ, ΜΥΤΙΛΗΝΗ,ΧΙΟΣ,ΣΑΜΟΣ,ΠΑΤΡΙΔΑ,ΒΙΒΛΙΟ,ΕΡΕΥΝΑ,ΠΟΛΙΤΙΚΗ,ΚΥΝΗΓΕΤΙΚΑ,ΚΥΝΗΓΙ,ΘΡΙΛΕΡ, ΠΕΡΙΟΔΙΚΟ,ΤΕΥΧΟΣ,ΜΥΘΙΣΤΟΡΗΜΑ,ΑΔΩΝΙΣ ΓΕΩΡΓΙΑΔΗΣ,GEORGIADIS,ΦΑΝΤΑΣΤΙΚΕΣ ΙΣΤΟΡΙΕΣ, ΑΣΤΥΝΟΜΙΚΑ,ΦΙΛΟΣΟΦΙΚΗ,ΦΙΛΟΣΟΦΙΚΑ,ΙΚΕΑ,ΜΑΚΕΔΟΝΙΑ,ΑΤΤΙΚΗ,ΘΡΑΚΗ,ΘΕΣΣΑΛΟΝΙΚΗ,ΠΑΤΡΑ, ΙΟΝΙΟ,ΚΕΡΚΥΡΑ,ΚΩΣ,ΡΟΔΟΣ,ΚΑΒΑΛΑ,ΜΟΔΑ,ΔΡΑΜΑ,ΣΕΡΡΕΣ,ΕΥΡΥΤΑΝΙΑ,ΠΑΡΓΑ,ΚΕΦΑΛΟΝΙΑ, ΙΩΑΝΝΙΝΑ,ΛΕΥΚΑΔΑ,ΣΠΑΡΤΗ,ΠΑΞΟΙ
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DIONYSODORUS 219<br />
generates the <strong>to</strong>re, and c the distance <strong>of</strong> its centre <strong>from</strong> the<br />
axis <strong>of</strong> revolution,<br />
(volume <strong>of</strong> <strong>to</strong>re) \ttc 2 .d = ^7rd 2 :^cd i<br />
2<br />
that is, (volume <strong>of</strong> <strong>to</strong>re) = \tt . cd<br />
2 ,<br />
which is <strong>of</strong> course the product <strong>of</strong> the area <strong>of</strong> the generating<br />
circle and the length <strong>of</strong> the path <strong>of</strong> its centre <strong>of</strong> gravity. The<br />
form in which the result is stated, namely that the <strong>to</strong>re is <strong>to</strong><br />
the cylinder with height d and radius c as the generating<br />
circle <strong>of</strong> the <strong>to</strong>re is <strong>to</strong> half the parallelogram cd, indicates<br />
quite clearly that Dionysodorus proved his result <strong>by</strong> the same<br />
procedure as that employed <strong>by</strong> Archimedes in the Method and<br />
in the book On Conoids and Sjjheroids ; and indeed the pro<strong>of</strong><br />
on Archimedean lines is not difficult.<br />
Before passing <strong>to</strong> the mathematicians who are identified<br />
with the discovery and development <strong>of</strong> trigonometry, it will<br />
be convenient, I think, <strong>to</strong> dispose <strong>of</strong> two more mathematicians<br />
belonging <strong>to</strong> the last century B.C., although this involves<br />
a slight departure <strong>from</strong> chronological order ; I mean Posidonius<br />
and Geminus.<br />
Posidonius, a S<strong>to</strong>ic, the teacher <strong>of</strong> Cicero, is known as<br />
Posidonius <strong>of</strong> Apamea (where he was born) or <strong>of</strong> Rhodes<br />
(where he taught) ; his date may be taken as approximately<br />
135-51 B.C. In pure <strong>mathematics</strong> he is mainly quoted as the<br />
author <strong>of</strong> certain definitions, or for views on technical terms,<br />
e.g. theorem and problem ' ' ' ', and subjects belonging <strong>to</strong> elementary<br />
geometry. More important were his contributions<br />
<strong>to</strong> mathematical geography and astronomy. He gave his<br />
great work on geography the title On the Ocean, using the<br />
word which had always had such a fascination for the <strong>Greek</strong>s<br />
;<br />
its contents are known <strong>to</strong> us through the copious quotations<br />
<strong>from</strong> it in Strabo ; it dealt with physical as well as mathematical<br />
geography, the zones, the tides and their connexion<br />
with the moon, ethnography and all sorts <strong>of</strong> observations made<br />
during extensive travels. His astronomical book bore the<br />
title Meteorologica or nepl uereoopcov, and, while Geminus<br />
wrote a commentary on or exposition <strong>of</strong> this<br />
work, we may<br />
assign <strong>to</strong> it a number <strong>of</strong> views quoted <strong>from</strong> Posidonius in<br />
220 SUCCESSORS OF THE GREAT GEOMETERS<br />
Cleomedes's work De motu circulari corporum caelestium.<br />
Posidonius also wrote a separate tract on the size <strong>of</strong> the sun.<br />
The two things which are sufficiently important <strong>to</strong> deserve<br />
mention here are (1) Posidonius's measurement <strong>of</strong> the circumference<br />
<strong>of</strong> the earth, (2) his hypothesis as <strong>to</strong> the distance and<br />
size <strong>of</strong> the sun. *<br />
(1) He estimated the circumference <strong>of</strong> the earth in this<br />
way. He assumed (according <strong>to</strong> Cleomedes l ) that, whereas<br />
the star Canopus, invisible in Greece, was just seen <strong>to</strong> graze the<br />
horizon at Rhodes, rising and setting again immediately, the<br />
'<br />
meridian altitude <strong>of</strong> the same star at Alexandria was a fourth<br />
part <strong>of</strong> a sign, that is, one forty-eighth part <strong>of</strong> the zodiac<br />
circle' (= 7-|°) ; and he observed that the distance between<br />
the two places (supposed <strong>to</strong> lie on the same meridian) ' was<br />
considered <strong>to</strong> be 5,000 stades'. The circumference <strong>of</strong> the<br />
earth was thus made out <strong>to</strong> be 240,000 stades.<br />
Unfortunately<br />
the estimate <strong>of</strong> the difference <strong>of</strong> latitude, 7^°, was very far<br />
<strong>from</strong> correct, the true difference being 5^° only ; moreover<br />
the estimate <strong>of</strong> 5,000 stades for the distance was incorrect*<br />
being only the maximum estimate put upon it <strong>by</strong> mariners,<br />
while some put it<br />
<strong>of</strong> the shadows <strong>of</strong> gnomons, found it<br />
at 4,000 and Era<strong>to</strong>sthenes, <strong>by</strong> observations<br />
<strong>to</strong> be 3,750 stades only.<br />
Strabo, on the other hand, says that Posidonius favoured the<br />
latest <strong>of</strong> the measurements which gave the smallest dimensions<br />
<strong>to</strong> the earth, namely about 180,000 stades'. 2 This is<br />
evidently 48 times 3,750, so that Posidonius combined Era<strong>to</strong>sthenes's<br />
figure <strong>of</strong> 3,750 stades with the incorrect estimate<br />
<strong>of</strong> 7\° for the difference <strong>of</strong> latitude, although Era<strong>to</strong>sthenes<br />
presumably obtained the figure <strong>of</strong> 3,750 stades <strong>from</strong> his own<br />
estimate (250,000 or 252,000) <strong>of</strong> the circumference <strong>of</strong> the earth<br />
combined with an estimate <strong>of</strong> the difference <strong>of</strong> latitude which<br />
was about 5-1° and therefore near the truth.<br />
5<br />
(2) Cleomedes 3 tells us that Posidonius supposed the circle<br />
in which the sun apparently moves round the earth <strong>to</strong> be<br />
10,000 times the size <strong>of</strong> a circular section <strong>of</strong> the earth through<br />
its centre, and that with this assumption he combined the<br />
1<br />
Cleomedes, Be motu circulari, i. 10, pp. 92-4.<br />
2<br />
Strabo, ii. c. 95.<br />
3<br />
Cleomedes, op. cit. ii. 1, pp. 144-6, p. 98. 1-5.