of a place, they batter the upper parts of the walls with rams; for anything standing up and projecting is easily broken and easily demolished, as it is detached and unconnected, such as are the battlements and the outworks and whatever things are not supported by being connected to one another. 250 And through the ram itself, since it is square, they will be able to cross easily to the wall, similarly to the side-railings attached to the towers. For these ladders will not be spun around, turning over on their rails, but will always remain standing and will keep the same intervals with respect to one another. And the drawing is set forth below. Again, the ladders take on another arrangement and position as they approach the wall, being equal and parallel or else upright [face-on], and they have their rungs facing toward the front of the wall and behind; and the intervals between them above and below are not unequal as in the first ones, but they maintain the same distance equally. and they have the same roofs as the former ones; but they also differ in this respect. For instead of the one ram carried between the two former ladders, two are brought up, placed outside against the sides of the rails. And these rams, having accomplished something or having moved or loosened something of the obstacles on the wall, the ropes from behind were slackened, and 251 together the two ladders advance toward the wall; one approaches the wall in front on its rungs; and the other stands off from it by the same interval that they are apart at the coupling, and it becomes a functional gangway to the wall. The coupling above the ladders, being decked and fenced. And the figure is shown below. And in this position and in the first one, without the aforementioned second one which is parallel in position and arrangement to the wall, while those on the rams are occupied, those standing on the roof and fighting from above create a clamor and strike terror into the enemy fight252ing in front; and having fenced with hides the two rungs projecting above upon the movement of the ram, they will provide for themselves a bulwark and a guard, like the battlements of a wall. And the double ladders will provide no small utility for safe assistance and service, if for each of the composite structures we place straight timbers of unequal width from a pin of equal height to the opposite one of equal height on the other ladder, that is, to the rung on each under the same roof at the same measure as that of the other; these timbers are to extend beyond the projecting ends of the pins and be immovable, preserving the intervals separating the ladders from one another at the rails, so that they are able neither to spread apart during movement nor to close up completely. And so that the timbers may not be pulled out nor fall from their secured place, let clamps sitting upon the rails of the ladders be nailed on, like the aforementioned engraved hemispheres or knobs cut around the middle, in order to tighten and hold fast the timbers attached to the pins. And the ram, which the ladders carry in the middle, should take on two square attach253ments on either of its sides at its front end, like little jaws, upright in height, rising up above the ram for up to a cubit, and secured for nailing also from below on account of the tension of the force. And let these be bored straight through opposite one another toward the middle, and on the outer parts of the holes let strong collars be nailed, like rings, receiving in their middle the so-called *choinikides*, which are similar in shape to earthenware pipe-sockets, worked from bronze on a lathe on the inside or bound on the outside with stout iron plates, having wider bases around their setting, and being prevented by the nailed-on rings from slipping out of the places of the holes during rotation. And let the mouths of the *choinikides* be cut back and receive square bars entering like sleeves, toward the ends
χωρίου ἐπὶ τὰ ἀνώτερα μέρη τῶν τειχῶν κριομαχῶσιν· εὔθραυστον γὰρ καὶ εὐκατάλυτον πᾶν τὸ ἀνεστηκὸς καὶ προέχον ὡς ἀπολελυμένον καὶ ἀσύνδετον, οἷαί τε εἰσὶν αἱ ἐπάλξεις καὶ τὰ προπύργια καὶ ὅσα μὴ πρὸς ἄλληλα συνεχόμενα ἐπιστηρίζονται. 250 Καὶ δι' αὐτοῦ τοῦ κριοῦ τετραγώνου ὄντος δυνήσονται εὐκόλως ἐπὶ τὸ τεῖχος διέρχεσθαι, ὁμοίως τοῖς ἐπὶ τῶν πύργων προσηρτημένων ἐπὶ τὰ πλάγια περιφραγῶν. Αἱ γὰρ κλίμακες αὗται οὐ περιστραφήσονται ἐπὶ τοὺς μηροὺς περιτρεπόμεναι, ἀλλὰ μενοῦσιν ἀεὶ ἐφεστῶσαι καὶ τὰ αὐτὰ συντηροῦσαι πρὸς ἀλλήλας διάχωρα. Καὶ ἡ καταγραφὴ πρόκειται. Πάλιν ἄλλην τάξιν καὶ θέσιν αἱ κλίμακες λαμβάνουσι τὴν πρὸς τῷ τείχει ἐπερχομένην, ἴσην οὔσαν καὶ παράλληλον ἤτοι ὀρθὴν [κατὰ πρόσωπον], καὶ τὰς μὲν βαθμίδας κατὰ πρόσωπον τοῦ τείχους καὶ ὄπισθεν ἀφορώσας ἔχουσι· τὰ δὲ ἀπ' ἀλλήλων διάχωρα ἄνω τε καὶ κάτω οὐχ ὡς αἱ πρῶται ἄνισα ἔχουσιν, ἀλλ' ἐξ ἴσου τὸ αὐτὸ συντηροῦσι διάστημα. στέγας δὲ τὰς αὐτὰς τῶν προτέρων ἔχουσι· παραλλάσσουσι δὲ καὶ κατὰ τοῦτο. Ἀντὶ γὰρ τοῦ ἑνὸς κριοῦ τοῦ μεταξὺ τῶν προτέρων δύο κλιμάκων φερομένου δύο ἔξωθεν πρὸς τὰ τῶν μηρῶν πλάγια τιθέμενοι ἐπιφέρονται. Οὗτοι δὲ οἱ κριοὶ κατεργασάμενοί τι ἢ μετακινήσαντες ἢ λύσαντές τι τῶν προκειμένων τῷ τείχει, προσεχαλῶντο τὰ ἐκ τῶν ὄπισθεν σχοινία, καὶ 251 ὁμοῦ τῷ τείχει αἱ δύο ἐπέρχονται κλίμακες· ἄλλη μὲν ἔμπροσθεν ἐπὶ τοὺς βαθμοὺς αὐτῆς προσεγγίζει τῷ τείχει· ἀφίσταται δ' ἀπ' αὐτῆς ἡ ἑτέρα, ὅσον καὶ τὸ πρὸς ἀλλήλας κατὰ τὴν ἐπίζευξιν ἀπέχει διάχωρον, καὶ γίνεται πρὸς τὸ τεῖχος ἐνεργὴς ἀναβάθρα. Καταστρωθεῖσα καὶ περιφραττομένη ἡ ἄνωθεν τῶν κλιμάκων ἐπίζευξις. Καὶ τὸ σχῆμα ὑπόκειται. Καὶ ἐπὶ ταύτης τῆς θέσεως καὶ ἐπὶ τῆς πρώτης, ἄνευ τῆς προρρηθείσης δευτέρας τῆς παραλλήλου τῇ θέσει καὶ τάξει πρὸς τῷ τείχει, τῶν ἐπὶ τῶν κριῶν ἀσχολουμενῶν οἱ ἐπὶ τῇ στέγῃ ἑστῶτες καὶ ἄνωθεν προμαχοῦντες θορυβοῦσι καὶ καταπλήττουσι τοὺς προ252 μαχοῦντας πολεμίους· δύο δὲ τοὺς ὑπερέχοντας ἄνωθεν βαθμοὺς ἐπὶ τῇ τοῦ κριοῦ γενομένῃ κινήσει βύρσαις περιφράξαντες, προτείχισμα καὶ φυλακὴν ὡς ἐπάλξεις τείχους ἑαυτοῖς παρέξουσιν. Οὐ μικρὰν δὲ εὐχρηστίαν πρὸς ἀσφαλῆ βοήθειαν καὶ ὑπηρεσίαν αἱ διπλαῖ παρέξουσι κλίμακες, ἐὰν καθ' ἑκάστην τῶν συγκειμένων ἀπὸ τῆς ἰσοϋψοῦς περόνης ἐπὶ τὴν τῆς ἑτέρας κατέναντι ἰσοϋψῆ, ἤτοι ἐπὶ τὸν ὁμοστεγῆ ἑκάστης βαθμὸν, κατὰ τὸ αὐτὸ μέτρον ἐπὶ τὸν τῆς ἑτέρας ξύλα ἑτεροπλατῆ ἐπ' εὐθείας παραθήσομεν πρὸς τὰ παρεξέχοντα ἄκρα τῶν περονῶν ὑπερβαίνοντα καὶ ἀπαράτρεπτα, φυλάττοντα τὰ ἀπ' ἀλλήλων τῶν κλιμάκων ἐπὶ τοὺς μηροὺς ἀφεστῶτα διάχωρα, μήτε ἐπανοίγεσθαι ἐπὶ τῇ τῆς φορᾶς κινήσει δυνάμενα, μήτε τὸ σύνολον ἐπικλείεσθαι. Ἵνα δὲ μὴ ἐκσπῶνται τὰ ξύλα μηδὲ ἐκπίπτωσι τοῦ κρατουμένου τόπου, χελωνάρια ἐπικαθήμενα ἐπὶ τοὺς τῶν κλιμάκων μηροὺς προσηλούσθωσαν ὡς τὰ προειρημένα ἐγγεγλυμμένα ἡμισφαίρια ἢ τὰ κατὰ μέσον περικεκομμένα γρονθάρια πρὸς τὸ ἐπισφίγγειν καὶ ἐπικρατεῖν τὰ ταῖς περόναις προσπεφυκότα ξύλα. Ὁ δὲ κριός, ὃν κατὰ μέσον αἱ κλίμακες φέρουσιν, ἐξ ἑκατέρων τῶν πλαγίων κατὰ τὸ ἔμπροσθεν ἄκρον προσλάβοι ἐπιπήγματα δύο τετρά253 γωνα, καθάπερ σιαγόνια, ὀρθὰ πρὸς ὕψος, ὑπερανεστηκότα τοῦ κριοῦ πήχεως ἄχρι, εἰς δὲ τὴν προσήλωσιν καὶ κάτωθεν διὰ τὴν τάσιν τοῦ τόνου ἀσφαλιζόμενα. Ταῦτα δὲ τρυπάσθωσαν ἐπ' εὐθείας ἀπεναντίον ἀλλήλων πρὸς τὸ μέσον, καὶ ἐπὶ τὰ ἔξωθεν μέρη τῶν τρημάτων προσηλούσθωσαν στεφάναι στερεαὶ καθάπερ κρίκοι, δεχόμεναι κατὰ μέσον τὰς λεγομένας χοινικίδας, ὁμοιουμένας ἐν σχήμασιν ὀστρακίνοις σωληνιδίοις, ἐκ χαλκοῦ εἰργασμένας ἀπὸ τόρνου ἔσωθεν ἢ ἐξ εὐτόνων σιδηροῖς ἔξωθεν ἐνδεδεμένας πετάλλοις, εὐρυτέρας βάσεις περὶ τὴν θέσιν ἐχούσας, καὶ κατὰ τὴν περιστροφὴν ὑπὸ τῶν προσηλωθέντων κρίκων κωλυομένας τοῦ παρεκπίπτειν τοὺς τῶν τρημάτων τόπους. Τὰ δὲ τῶν χοινικίδων ἀνακοπέτωσαν στόμια καὶ δεχέσθωσαν κανόνια τετράγωνα ἐπεμβαίνοντα ὡσανεὶ περιστομίδας, πρὸς τὰ ἄκρα