COSMOS, VOL. II - World eBook Library

544 COSMOS.
from west to east in the parallel of Rhodes (in the diaphragm
of Dicsearchus).*
An animated desire to arrive at a generalisation of views,
the consequence of the intellectual movement of the age,
gave rise to the first Greek measurement of degrees between
Syene and Alexandria, and this experiment may be regarded
as an attempt on the part of Eratosthenes to arrive at an approximative
determination of the circumference of the earth. In
this case,
imperfect premises afforded by the Bematists which excites
our interest, but rather the attempt to rise from the narrow
it is not the result at which he arrived from the
limits of one circumscribed land to a knowledge of the magnitude
of the whole earth.
A similar tendency towards generalisation may be traced in
the splendid progress made in the scientific knowledge of the
heavens in the epoch of the Ptolemies. I allude here to the
determination of the places of the fixed stars by the earliest
Alexandrian astronomers, Arystillus and Timochares to Aris-
;
tarchus of Samos, the cotemporary of Cleanthes, who, conversant
with ancient Pythagorean views, ventured upon an
investigation of the construction of the universe, and who was
the first to recognise the immeasurable distance of the region
of fixed stars from our small planetary system ; nay,
he even
the twofold motion of the earth round its axis and
conjectured
round the sun; to Seleucus of Erythrsea (or of Babylon),f who
* Strabo, lib. xi. p. 519; Agathem, in Hudson, Geogr. grcec. min.,
vol. ii. p. 4. On the accuracy of the grand orographic views of
Eratosthenes, see my Asie centrale, t. i. pp. 104-150, 198, 208-227,
413-415; t. ii. pp. 367 and 414-435; SindExamen critique de I'Hist. de
la Geogr., t. i. pp. 152-154. I have purposely called the measurement
of a degree made by Eratosthenes, as the first Hellenic one, since a very
ancient Chaldean determination of the magnitude of a degree in camels'
paces is not improbable. See Chasles, JRecherches sur I'Astronomic
indienne et chaldeenne, in the Comptes rendus de I'Acad. des Sciences,
t. xxiii. 1846, p. 851.
f The latter appellation appears to me the more correct, since Strabo,
"
lib. xvi. p. 739, quotes, Seleucus of Seleucia, among several very
honourable men, as a Chaldean, skilled in the study of the heavenly
bodies." Seleucia, on the Tigris, a flourishing commercial city, is
probably the. one meant. It is indeed singular, that Strabo also speaks of
a Seleucus, an exact observer of the tides, and terms him, too,
a Babylonian (lib. i. p. 6), and subsequently (lib. iii. p. 174), perhaps
from carelessness, an Erythreean. (Compare Stobaeus, Eel. pliys., p. 440.)