even from the first, while the further that the mole was advanced into the sea, the more difficult and dangerous became its construction. The channel deepened gradually from a few feet towards the shore to eighteen or twenty,[14380] as it approached the island. The Tyrians in their vessels were soon able to act. In small boats at first, and afterwards in their triremes, they attacked and annoyed the workmen, perpetually hindered their work, and occasionally destroyed portions of it.[14381] Damage was also inflicted by the wind and waves; and the rate of progress became, in consequence, exceedingly slow. A strong current set through the channel, and this was continually working its way among the interstices of the mole, washing holes in its sides and face, and loosening the interior of the structure. When a storm arose, the surf broke over the top of the work, and did even greater damage, carrying portions of the outer casing into the sea. To meet the assaults of the Tyrian ships upon the work, the Macedonians constructed two movable towers, well protected against torches and weapons by curtains made of raw hides,[14382] and advancing these upon the surface of the mole to the points most threatened, discharged from the engines which the towers contained darts and stones of a large size against the Tyrian sailors. Thus protected, the workmen were able to make sensible progress, and the Tyrians began to fear that, unless they could destroy the towers, the mole would ere long be completed. For the accomplishment of their purpose, they resolved to employ a fire-ship.[14383] Selecting one of the largest of their horse-transports, they stowed the hold with dry brushwood and other combustible materials; and erecting on the prow two masters, each with a projecting arm, attached to either a cauldron, filled with bitumen and sulphur, and with every sort of material apt to kindle and nourish flame. By loading the stern of the transport with stones of a large size, they succeeded in depressing it and correspondingly elevating the prow, which was thus prepared to glide over the smooth surface of the mole and bring itself into contact with the towers. In the fore part of the ship were deposited a quantity of torches, resin, and other combustibles. Watching an opportunity when the wind blew strongly from the seaward straight upon the mole, they towed the vessel at their best speed in the direction of the towers, set it on fire, and then, loosing their hawsers, allowed it to dash itself upon the work. The prow slid over the top a certain distance and then stopped. The arms projecting from the masts broke off at the sudden check,[14384] and scattered the contents of the cauldrons around. The towers caught fire and were at once in a blaze. The Macedonians found it impossible to extinguish the flames, since the Tyrian triremes, drawing close to the mole, prevented approach by flights of arrows and other missiles. “At the same time,