Mauretanians hunt hearing; a well steals camp talk
Theft of sound. The Mauretanians see sharpest of all. They recognize one approaching from far off, and they hear equally, though hearing is slower than seeing. Their sight is long by exercise and by nature: besides the runs they train, breathing very light air, they also abstain from everything hot and from salts, as being causes of dim sight.
So that they may never be caught sleeping, and an approach of enemies not escape them at night, they set under the neck that sleeping-wood of theirs, leaving the ear unhindered for hearing, dig a little pit, and hear both from far off — both voice and shouts. I have heard that the brigands of the western Gauls do the same. This is an improvised hunting of hearing.
If someone in a great camp should wish to learn the counsels of his own soldiers, or the secrets of the enemy — Art of knowing things to come — having dug a deep well, let him let down whom he wants, covering the mouth with some cloak. Nothing will escape the one sitting in it; he will recount to you what was said or what sounded, as if prophesying.
Let everyone trust my word: the one hunting long hearing by sitting with it, and the other, on a lightless night, to see something hidden on the earth, reasonably without fire. For the higher air is full of sound, and the plain earth strikes the sight with thickness and dulls the hearing with noise.
Greek
1.16 Ἤχου κλοπή Ὀξύτατα πάντων ὁρῶσι Μαυρούσιοι καὶ τὸν προσιόντα γνωρίζουσι μακρόθεν καὶ ἀκούουσιν ἴσα, καίτοι τῆς ἀκοῆς βραδυτέρας οὔσης τοῦ βλέπειν. Ἀλλ' ἡ μὲν ὄψις αὐτοῖς ἀσκήσει καὶ φύσει μακρά· πρὸς γὰρ οἷς γυμνάζονται δρόμοις, ἀναπνέοντες ἀέρα κουφότατον, ἔτι καὶ ἀπέχονται θερμοῦ τε παντὸς καὶ ἁλῶν, ὡς ὄντων τοῦ ἀμβλυώττειν αἰτίων. Ὡς δ' ἂν μή ποτε ἁλῶσιν καθεύδοντες καὶ ἔφοδος αὐτοὺς πολεμίων μὴ λάθῃ νύκτωρ, οἵδε ὑπερεισάμενοι τῷ αὐχένι τὸ εὐναστήριον ἐκείνοις ξύλον, ἀκώλυτον εἰς ἀκοὴν ἀφέντες τὸ οὖς, ὀλίγον ὑποσκάπτουσι βόθρον καὶ ἀμφοτέρων ἀκούουσι μακρόθεν καὶ φωνῆς καὶ ἀϋτῶν. Τὸ δὲ αὐτὸ δρᾶν καὶ τοὺς Γαλατῶν τῶν ἑσπερίων ἤκουσα λῃστάς. Αὐτοσχέδιος αὕτη θήρευσις ἀκοῆς. Ὡς ἂν δέ τις ἐν μεγάλῳ στρατοπέδῳ τὰ τῶν αὑτοῦ στρατιωτῶν βουλεύματα ἢ τὰ τῶν πολεμίων ἀπόρρητα ἐθελήσῃ μαθεῖν, [Τέχνη προγνωστικὴ τῶν μελλόντων] φρέαρ ὀρύξας βαθύ, ὃν βούλεται καθιέτω, ἐπικαλύψας τὸ στόμιον ἱματίῳ τυχόντι· οὐδὲν τὸν ἐγκαθήμενον λήσεται, ἀλλά σοι τὰ εἰρημένα ἢ τὰ ἠχήσαντα ὡς μαντευόμενος διηγήσεται. Πιστευέτω μου τῷ λόγῳ πᾶς, ὃ μὲν μακρὰν θηρώμενος ἀκοὴν συγκαθεσθείς, ὃ δὲ νυκτὸς ἀλαμποῦς τῶν τι κρυπτομένων ἰδεῖν ἐπὶ γῆς, ἄνευ πυρὸς εἰκότως. Ὁ γὰρ ὑψηλότερος ἀὴρ ἠχοῦς ἐστι μεστός, καὶ ἡ γῆ ἁπλῆ τὴν ὄψιν ἐκπλήττει τῇ παχύτητι τῷ τε θορύβῳ τὴν ἀκοὴν ἀμβλύνει.