210 HISTORICAL GEOGRAPHY. [CHAP.
«
into the Atlantic—the Baetis, the Anas, and the Tagus, but that
he attempts to estimate the length of the last-named stream from
its source to its mouth, assigning to it a course of 8000 stadia1.
His account of the silver mines in the neighbourhood of New
Carthage, also, is evidently derived from personal enquiry, for he
mentions the number of slaves employed there, and the amount of
revenue derived from them, and describes in detail the process by
which the ore was prepared for smelting*. The Alps, again, he has
graphically depicted, and he mentions the four passes which were
known at that time to lead through them, viz. that which skirts the
Ligurian sea, that which passes through the land of the Taurini
(the Mont Genfevre), that through the territory of the Salassi (the
Little St. Bernard), and that by way of Rhaetia (the Brenner)8.
The advantage which he had himself received from
His Opinion .
of the import- these journeys impressed him so forcibly, that he
ance of Travel. came tQ ^rd travel as an essential part of the
equipment of the historian and geographer; insomuch that he
finds fault with Timaeus as a historical writer, because he ignored
altogether this source of evidence—"for/1 says Polybius, "the
eyes are more accurate witnesses than the ears4.1' One result of
the experience of travelling in his case was the interest which he
interest in was ^ to ta^ce *n Physical geography, a notable
Physical Geo- instance of which is found in his account of the
graphy' volcanic island of Hiera (Vulcano) in the Lipari
group, the condition of the craters of which he describes, and the
way in which it is affected by the winds which blow from different
quarters5. He also remarks concerning the stream of the Timavus,
which rises about a mile from the sea at the head of the Adriatic,
that its sources with one exception are brackish, so that the
natives call the spot the fountain-head and mother of the sea*.
The accuracy of his observation has in this case been strikingly
confirmed by modern research; for, whereas he alone of the
ancient writers who h^ve described that river mentions this pecu-
liarity, it is noticed also by Cluver, the greatest modern authority
on the geography of Italy, who says that at high tides all the
1 Strabo, 2. 4. 4. a .##., 3. 2. IO.
1 Ibid., 4. 6. 13. 4 polyb., I2. 27. j—3.
* Stiabo, 6. 2.10. » aid., 5. i. 8.