Leonid Zhmud The Origin of the History of Science in Classical Antiquity

op. cit., 119f. It remains uncertain whether the
evidence that Thales “was the first to determine the sun’s course from solstice to sol-
stice” goes back to Eudemus (D. L. I, 24: prõto~ dè kaì t3n @pò trop4~ ëpì
trop3n párodon e0re). Diogenes does not name his source.
72
The length of the seasons, starting with the summer solstice, is 92½, 88¹
⁄
8
, 90¹
⁄
8
and
94½ days.
73
In Hesiod, tropaí refers not to a particular day, but to the season when the winter or
the summer solstice occurs. See Kahn, C. H. On early Greek astronomy,
JHS 90
(1970) 113.
74
The connection between Thales’ observation of solstices with the estimation of the
solar year’s length is indirectly confirmed by the fact he is credited with the division
of the year into 365 days (D. L. I, 27). The intercalation period of 8 years introduced
in the late sixth century by Cleostratus (6 B 4) presumed the year to be 365¼ days
long (Samuel,
op. cit., 35f., 40; van der Waerden. Astronomie, 26f.). Neugebauer
(
HAMA II, 620f.), though discussing the octaëteris, leaves the question of its author
open, for the existence of Greek astronomy in the sixth century does not fit his con-
ception.

---

2. Thales and Anaximander
245
94 days.
75
The difference between semi-annual periods amounts, respectively,
to 5 or 3 days. Thales’ own estimate remains unknown.
Less plausible is the suggestion that Dercyllides–Theon (fr. 145) points to
the inequality of the
four seasons marked off by the solstices and equinoxes.
76
The problem is that Eudemus’ evidence on Thales is silent on equinoxes.
77
Meanwhile, reconstructing Eudemus’ reports on Thales
, one should not ascribe
to the latter anything that goes beyond the evidence safely attributable to the
History of Astronomy, particularly if it is not confirmed by independent and re-
liable sources. In this case, late sources unanimously assert that the first to have
determined solstices and equinoxes by means of the gnomon was Anaximan-
der.
78
We do not know the extent to which this view was shared by Eudemus. It
is obvious, in any case, that there is no compelling reason to link the equinoxes
with Thales.
Eudemus has only two direct testimonies of Anaximander’s astronomical
discoveries. The first is found in Dercyllides–Theon’s list of discoveries:
^Anaxímandro~ dè Ôti ëstìn 1 g4 metéwro~ kaì kine$tai perì tò toñ kósmou
méson.
Anaximander (was the first to discover) that the earth is freely suspended and
moves about the center of the cosmos (fr. 145).
The second is cited by Simplicius when he comments on Aristotle’s statement
that the relative position of heavenly bodies and the distances between them
may best be studied in astronomical writings:
79
^Anaximándrou prõtou tòn perì megeqõn kaì @posthmátwn (sc. tõn pla-
nwménwn) lógon eûrhkóto~, !~ EÚdhmo~ îstore$ t3n t4~ qésew~ táxin eı~
toù~ Puqagoreíou~ prøtou~ @naférwn.
75
These data are found in the second century BC papyrus known as
Ars Eudoxi
(col. XXIII). See Rehm, A. Das Parapegma des Euktemon,
SHAW Nr. 3 (1913) 8ff.;
Neugebauer.
HAMA II, 627.
76
Tannery.
Science hellène, 68; Heath. Aristarchus, 20; KRS, 83. Van der Waerden’s
explanation (
Astronomie, 11f.) is manifestly erroneous.
77
Unlike solstices, which are more or less easy to observe, equinoxes are determined
by calculations; besides, the word ıshmería is first attested in a Hippocratic treatise
of the late fifth century (