WITHOUT even pausing to see the effects of his charge upon the three air-ships above Alexandria, Alan kept the Avenger going at full speed, soaring up into the higher regions of the atmosphere with her prow pointed to the north-east. About three hours later she was floating at an elevation of nearly five miles above Moscow, not stationary, but sweeping round and round in vast circles on her quadruple wings after the manner of the condors of the Andes, which thus sustain themselves on almost motionless wings at vast elevations and very small expenditure of force.

Below an immense expanse of country lay in unclouded clearness under the glasses of the captain of the ship and George Cosmo, late engineer of the Narwhal, who was now chief engineer of the Aerian flagship.

Not only Moscow, but a dozen other towns lay at the mercy of the Avenger’s twenty-four guns, and yet no shot was fired, for Alan, despite the tremendous debt of vengeance that he owed to her who now, at last in very fact crowned Tsarina of the Russias, held her court at Moscow, was yet extremely loth to involve non-combatants in the destruction which he knew must follow the discharge of his guns.

Added to this, his present designs were rather to reconnoitre than to destroy. He was in command of the fastest and most powerful air-ship in the world, and the task that he had set himself was to supervise the whole of the complicated arrangements that had been made for repelling the coming attack upon the Federation by the Moslems and Russians.

Thus he had started soon after midnight from Gibraltar, one of the chief power-stations and depôts in Europe. Thence he had run along the African coast over Oran, Algiers, Tunis, and Tripoli, noting the sleepless activity of the brilliantly-lighted towns, the swarming transports and battleships in their harbours, and the crowds of anxious watchers in their streets. Then he had got round to the south of Alexandria, as has been seen, and there struck the first blow in the war.

Now, his object was to discover what disposition of troops were being made for the invasion of Austria and Germany. Another scout-ship would be by this time floating over St. Petersburg, and another over Odessa, and these were to report to him at noon.

He had kept the Avenger moving with sufficient rapidity to make it extremely difficult for her to be seen from the earth, as he wanted to see without being seen, and he remained undiscovered until nearly noon. All this time trains had been seen running in swift succession into Moscow from the east and out to the west, evidently conveying troops to the frontier.

A large fleet of air-ships, numbering apparently between two and three hundred vessels, were seen lying in four squadrons on the open space about the Kremlin, and others were constantly flying into and out of the city in all directions.

A few minutes after half-past eleven, Cosmo, after a long look through his glasses, called to Alan, who was looking out from the other side of the deck—