To destroy the air-ships seemed an impossibility, since they could move at five times the speed of the swiftest aerostat, and yet to return to the bombardment of the city was to leave them free to commit what havoc they pleased upon the encampments of the armies of the League. So they were drawn farther and farther away from the beleaguered city, while their agile enemies, still keeping within their six-mile range, evaded their shells, and yet kept up a constant discharge of their own projectiles upon the salient points of the attack on London. By four o'clock in the afternoon all the batteries of the besiegers had been put out of action by the aërial bombardment. It was now a matter of man to man and steel to steel, and so the gage of final battle was accepted, and as dusk began to fall over the beleaguered city, the Russian, French and Italian hosts left their lines, and descended from their vantage ground to the assault on London, where the old Lion at bay was waiting for them with claws bared and teeth grinning defiance. CHAPTER XLIV. THE TURN OF THE BATTLE-TIDE. The force which the Tsar had detached to operate against the Federation Army of the North left the headquarters at eleven o'clock, and proceeded in four main divisions by Edmonton, Chingford, Chigwell, and Romford. The aerostats, regulating their speed so as to keep touch with the land force, maintained a position two miles ahead of it at three thousand feet elevation. Strict orders had been given to press on at the utmost speed, and to use every means to discover the Federationists, and bring them to an engagement with as little delay as possible; but they marched on hour after hour into the dusk of the early winter evening, with the sounds of battle growing fainter in their rear, without meeting with a sign of the enemy. As it would have been the height of imprudence to have advanced in the dark into a hostile country occupied by an enemy of great but unknown strength, General Pralitzin, the Commander of the Russian force, decided to bring his men to a halt at nightfall, and therefore took up a series of positions between Cheshunt, Epping, Chipping Ongar, and Ingatestone. From these points squadrons of Cossacks scoured the country in all directions, north, east, and west, in search of the so far invisible army; and at the same time he sent mounted messengers back to headquarters to report that no enemy had been found, and to ask for further orders. The aerostats slowed down their engines until their propellers just counteracted the force of the wind and they hung motionless at a height of a thousand feet, ranged in a semicircle about fifteen miles long over the heads of the columns.