The first and chief endeavour of the captain of every vessel was to avoid the shots of his opponents and to get his own home. It was brains and machinery pitted against brains and machinery, and grappling was never thought of. The air-ship which could gain and maintain a greater elevation than her opponent infallibly destroyed her, and so, too, did the one that could fly unhurt at full speed along the line of battle and use her stern guns upon those which became relatively stationary enough for her to take aim at them. It would have been a magnificent spectacle for an observer who could have followed the contending squadrons in their swift and complicated evolutions. He would have seen the blue and the silver hulls flashing to and fro as though apparently engaged in some harmless trial of speed, then, without the slightest warning, without a puff of smoke or the faintest sound of a report, the long, deadly guns would do their work. The moment of vantage would come, and the silent and invisible messengers of annihilation would be sped upon their way; then, with a roar and a shock that convulsed the firmament, a mist of flame would envelop the ship that had been struck, and when it vanished she would have vanished too, falling in a rain of fragments towards the earth nearly twenty thousand feet below. It was a battle not so much for victory as for destruction. There could be no victory save to those who survived after having annihilated their enemies, and this was the sole object of the struggle. High in air above the contending squadrons, the _Avenger_ and the _Isma_ swept to and fro along the line, raised by their superior soaring powers beyond the zone of battle, and from their decks the two admirals commanded the fight, and, like very Joves above the tempest, hurled their destroying bolts from their terrible guns far and wide over the scene of strife. From morning to night both Alan and Alexis sought in vain for the blue hull of the _Revenge_ among the Russian squadron. Unless Olga was on board one of the other ships she was either engaged in some work of destruction elsewhere or was directing the operations of her forces and learning the disasters that had overtaken them in her palace in Moscow or St. Petersburg. It had been previously ordered that, as soon as it became too dark to take accurate aim with the guns, those vessels of the Aerian fleet which had survived the battle were to fly westward and rendezvous at midnight on the summit of the Schneekoppe, one of the peaks of the Giant Mountains to the north-east of Bohemia, whence, as soon as the amount of damage had been ascertained, the remainder of it, if strong enough, was to set out and if possible intercept the Moslem fleet before it could form a junction with the Russians.