Ἰνδικά 19.2: Strabo XV, p. 703

19.2

Ἐν δὲ τῇ ὀρεινῇ Σιλίαν (Σίλαν Epit. Strab.) ποταμὸν εἶναι (Megasthenes ait), ᾧ μηδὲν ἐπιπλεῖ· Δημόκριτον μὲν οὖν ἀπιστεῖν ἄτε πολλὴν τῆς Ἀσίας πεπλανημένον· καὶ Ἀριστοτέλης δὲ ἀπιστεῖ.

(Megasthenes says) that in the mountainous country is a river, the Silas, on the waters of which nothing will float. Demokritos, who had travelled over a large part of Asia, disbelieves this, and so does Aristotle.