July, 332 B. C.] In the sixth month from the commencement of the siege, the invaders had advanced to the foot of the walls, and in approaching they widened the Causeway, in order to enable them to have greater space for carrying on the operations of Storming the Capital. Upon the successful termination of constructing the Mole, the engines of ancient warfare were placed in their several localities for active service. In front, and near to the walls (which were of soft stone and stuccoed), were stationed several battering-rams of enormous magnitude and power, and swung from high triangles and towers, in order to batter the upper, and consequently the weakest part of the mural defence. Behind these engines, at a short distance, were placed the powerful Balistæ and Catapultæ for throwing stones and timber, darts and javelins into the city. In the third position from the walls, were stationed several high wooden-towers, from four to six stories in altitude, and manned with archers; each story had its drawbridge, both for defence, and to let down upon, or into any breach that might be made, and from which bridge the archers and spearmen could pass on to the walls, upon the huge machines being wheeled forward by the Soldiery in the rear of the towers. The now Grecian Galleys (captured from the Tyrians) were brought and moored along the sides of the Mole, having their lines trebled near, and especially at the Island-base of the causeway. This precaution was to prevent escape in case of any sortie; as, also, to give protection to the new Military work against the continual injury from the waves. This action and locality of the captured vessels _left the walls towards the Sea unwatched_, and it was considered by the invaders as useless to keep their small fleet dispersed, when no escape could be made by the Tyrians in that quarter, from the want of vessels; therefore, from the oblong form of the Island-Capital (its sides being parallel with the Sea and the mainland), _it would prevent those engaged at the Causeway, from seeing any movement or enterprise, that might be undertaken at the Seaward gates of the Metropolis_. This fact is of great importance, and for the full appreciation of the result, the reader should not let it escape from memory. During the successful advance, the Tyrians had been incessant in their defence of Nature's Moat; but, now that it was passed by the enemy, their only duty was to prevent a breach being made in the wall: this defence was comparatively easy, for the attack could only be made upon one point, and the only approach to that assault was over the Causeway.