§9.14.1τῶν δὲ προειρημένων τὰ μὲν ἐκ τριβῆς, τὰ δʼ ἐξ ἱστορίας, τὰ δὲ κατʼ ἐμπειρίαν μεθοδικὴν θεωρεῖται.
Of the aforementioned matters, some are studied through practical experience, some through inquiry, and some by methodical knowledge.
§9.14.2κάλλιστον μὲν οὖν τὸ γινώσκειν αὐτὸν καὶ τὰς ὁδοὺς καὶ τὸν τόπον, ἐφʼ ὃν δεῖ παραγενέσθαι, καὶ τὴν φύσιν τοῦ τόπου, πρὸς δὲ τούτοις, διʼ ὧν μέλλει καὶ μεθʼ ὧν πράττειν.
Now, the best thing is for the leader himself to know the roads, the place to which he must arrive, and the nature of that place, and in addition to these, the means through which and the persons with whom he is going to act.
§9.14.3δεύτερον δʼ ἱστορεῖν ἐπιμελῶς καὶ μὴ πιστεύειν τοῖς τυχοῦσι· τὴν δὲ τῶν καθηγουμένων πίστιν ἐπί τι τῶν τοιούτων ἐν τοῖς ἑπομένοις ἀεὶ δεῖ κεῖσθαι.
The second is to make diligent inquiry and not to trust any chance person; and the pledge given by the guides in such matters must always be placed in the hands of those who follow.
§9.14.4ταῦτα μὲν οὖν καὶ τὰ τούτοις παραπλήσια δυνατὸν ἴσως καὶ διʼ αὐτῆς τῆς στρατιωτικῆς τριβῆς περιγίνεσθαι τοῖς ἡγουμένοις, τὰ μὲν ἐξ αὐτουργίας, τὰ δʼ ἐξ ἱστορίας·
Indeed, these and similar matters can perhaps be acquired by leaders even through military experience itself, partly from their own labor and partly from inquiry.
§9.14.5τὰ δʼ ἐκ τῆς ἐμπειρίας προσδεῖται μαθήσεως καὶ θεωρημάτων, καὶ μάλιστα τῶν ἐξ ἀστρολογίας καὶ γεωμετρίας, ὧν τὸ μὲν ἔργον οὐ μέγα πρός γε ταύτην τὴν χρείαν, τὸ δὲ χρῆμα μέγα καὶ μεγάλα συνεργεῖν δυνάμενον πρὸς τὰς προειρημένας ἐπιβολάς.
But those which come from methodical knowledge require further learning and theoretical principles, especially those derived from astronomy and geometry, the study of which is not very great for this particular need, but their utility is great and capable of contributing much to the aforementioned undertakings.
§9.14.6ἀναγκαιότατον δʼ αὐτοῦ τὸ περὶ τὰς νυκτερινὰς θεωρίας καὶ τὰς ἡμερινάς.
Most necessary of this is the study of the night and day.
εἰ μὲν γὰρ ἴσας εἶναι συνέβαινεν ἀεὶ ταύτας, οὐδʼ ἧστινος ἂν ἀσχολίας τὸ πρᾶγμα προσεδεῖτο, κοινὴ δʼ ἂν ἦν ἁπάντων ἡ γνῶσις·
For if it happened that these were always equal, the matter would not require any trouble, and the knowledge of them would be common to all.
§9.14.7ἐπεὶ δʼ οὐ μόνον ἔχει τὰ προειρημένα πρὸς ἄλληλα διαφοράν, ἀλλὰ καὶ πρὸς αὑτά, δῆλον ὡς ἀνάγκη γινώσκειν τὰς αὐξήσεις καὶ μειώσεις ἑκατέρων.
But since the aforementioned days and nights not only differ from one another, but also within themselves, it is clear that one must know the increases and decreases of both.
§9.14.8πῶς γὰρ ἄν τις εὐστοχήσειε πορείας καὶ διανύσματος ἡμερησίου, πῶς δὲ νυκτερινοῦ, μὴ κατανοήσας τὰς τῶν προειρημένων διαφοράς;
For how could anyone hit upon the measure of a day's march and distance, and how upon a night's, without understanding the differences of the aforementioned?
§9.14.9καὶ μὴν οὐδὲν πρὸς τὸν δέοντα καιρὸν ἐξικέσθαι δυνατὸν ἄνευ τῆς τούτων ἐμπειρίας, ἀλλὰ ποτὲ μὲν ὑστερεῖν, ποτὲ δὲ προτερεῖν ἀνάγκη.
And indeed, it is impossible to arrive at the required time without knowledge of these, but one must either fall short or arrive too early.
§9.14.10μεῖζον δὲ τὸ προτερεῖν ἐν μόνοις τούτοις ἁμάρτημα τοῦ καθυστερεῖν·
And in these matters alone, arriving too early is a greater error than arriving too late.
§9.14.11ὁ μὲν γὰρ ὑπεράρας τὸν ὡρισμένον καιρὸν αὐτῆς ἀποτυγχάνει τῆς ἐλπίδος — τὸ γὰρ γεγονὸς ἐξ ἀποστήματος ἐπιγνοὺς αὖθις ἀπολύεται μετʼ ἀσφαλείας — ὁ δὲ προλαβὼν τὸν καιρόν, §9.14.12ἐγγίσας καὶ γνωρισθεὶς οὐ μόνον ἀποτυγχάνει τῆς ἐπιβολῆς, ἀλλὰ καὶ κινδυνεύει τοῖς ὅλοις.
For he who has passed the appointed time fails of his hope, yet having perceived what happened from a distance, he can withdraw again with safety; but he who arrives before the time, having drawn near and been discovered, not only fails in his undertaking, but also endangers the whole enterprise.