event of a defeat. If the line of the Euphrates or the Tigris could not be held in a war, if the Median wall and the four lines of the canals behind it between the Tigris and Euphrates were abandoned, if the army were forced behind all these or defeated in open field, it must be sure of finding certain protection behind the walls of the main city. When rested in this great open space, and again thoroughly armed, it could not only hold the walls with ease, for they, as we have seen, were so high and strong, that they almost defended themselves; it could sally forth for new encounters in the open field. If the enemy divided his forces in order to invest the city, the army of Babylon could attack either of these halves with the whole force, and thus had the best prospect of a successful battle. It certainly was not the furtherance of intercourse which primarily induced Nebuchadnezzar to build the permanent bridge; a bridge such as the enemy could not destroy by putting beams or heavily laden vessels into the river above the city secured for the army when it had retired into the city the speediest means of passing from bank to bank, and put it in a position to make a sudden onset on the right or left bank. Even if the worst happened, and the enemy succeeded in gaining possession of the city on the western or eastern bank, the bed of the bridge was easily thrown off, and the defence of the part of the city which was still uncaptured was scarcely rendered at all more difficult by the pillars. The fixing of the foundations of the shore walls which secured the new eastern as well as the old western part of the city against attempts of the enemy on vessels, and from the river, and which was intended to render possible the defence of each part of the city after the loss of the other, would be very difficult: the fixing of the foundations of the pillars of the bridge would be more difficult still, and the bridge could not be rendered secure against the force of the high flood without the basin of Sippara. We see how the buildings of Nebuchadnezzar hang together; they all spring from one conception, from one connected system.