1 The Birth of Science - MSRI

4.4 Sailing and Navigation 99
It was these “rediscoveries” that allowed the long open-sea voyages that
had been impossible in the Middle Ages. page 137
All of this would seem to suggest that the seafaring people who created
spherical geometry and trigonometry, mathematical astronomy, mathematical
geography, cartography and the astrolabe might also know how
to use these instruments for sailing, if only because the tie between Greek
astronomy and navigation was clearly present from the earliest, prescientific,
days. 64 Yet until not long ago it was believed that the “Ancients”
sailed only within sight of the coast, because this is what people did in the
Middle Ages, when all the scientific theories needed for open-seas navigation
had been lost.
Yet not only are there echos of Hellenistic oceanic voyages in the literature,
as part of fantastic tales such as Lucian’s True story 65 or Photius’
summary of the lost novel The incredible things beyond Thule by Antonius
Diogenes; 66 there are also reports of actual trips, such as that of Eudoxus of
Cyzicus, who sailed several times to Egypt and India not by skirting the
shore but along a direct ocean route from the Gulf of Aden, 67 or the exploratory
voyage in the North Atlantic made, probably in the late fourth
century B.C., by the Massalian Greek Pytheas and described in his book
The ocean ( ).
From fragments of this book and other information preserved by several
authors, 68 we know that Pytheas reached places where the sun stays up page 138
all night in summer (such as the island of Thule, six days of sailing north
64 The first “astronomical” work we know about is the Nautical astrology attributed to Thales
(Simplicius, In Aristotelis Physicorum libros commentaria, [CAG], vol. X, 23, 29) or to Phocus of Samos
(Diogenes Laertius, Vitae philosophorum, I, 23).
65 Lucian’s tale appears as a grotesque mass of obvious falsehoods because it is not simply a work
of fiction, but, as the author explains, a satire of travelogues he regards as untrustworthy. Therefore
we can be sure that various elements of the narration were present in supposedly realistic works.
At the same time, we know that Lucian’s contemporaries no longer lent credence even to Pytheas’
trip, of which we will soon say more.
66 According to Photius, the novel’s protagonist travels from the Scythian Ocean to the Eastern
Ocean and from there, skirting the Outer Sea, he reaches Thule, an island in the North Atlantic
(probably Iceland for Pytheas; but Ptolemy’s Thule has been identified with the Shetlands:
[Ptolemy/Toomer], p. 89, note 66).
67 These trips, dating form the time of Euergetes II, were narrated by Posidonius and are mentioned
in Strabo, Geography, II, iii, 4. In that period the interest of the Ptolemies in sailing in the
Indian Ocean is demonstrated by the naming, toward the end of the second century B.C., of a royal
officer (with authority over the Red Sea and the Indian
Ocean). See [Rostovtzeff: SEHHW], vol. II, p. 928 and neighboring pages (last four pages of Chapter
VI).
68 The fragments and other testimonia are collected in [Roseman].
Revision: 1.14 Date: 2002/10/24 04:25:47