What would have been in the nineteenth century a matter of weeks was now only one of days and hours. The enormously-developed system of intercommunication made transit, even for very large numbers of men and between very distant points, rapid to a degree undreamt of in the present century. Trains could travel at two hundred miles an hour along the hundreds of quadruple lines which covered the Continent with their gigantic network, aerial cruisers could fly at more than twice this speed, and squadrons of submarine battleships could cleave their silent and invisible way through the ocean depths at a hundred and fifty miles an hour. It was, therefore, almost impossible to tell without certain information where and how the blows of the enemy would be struck, or from how many points the European area of the Federation might be assailed at once, and vast indeed were the responsibilities and anxieties which weighed upon the man whose single brain was the centre of this vast and complicated system of defence, and on whose decisions would depend the safety or the destruction of millions of human beings. Alan had managed to get four hours’ sleep in the afternoon between Moscow and Gibraltar, and he snatched two hours more before midnight. Then he was called, and the _Avenger_ was just about to take the air to return to the Russian frontier, so that he might supervise the operations there, when the look-out on the summit of the Rock of Gibraltar saw and answered the Aerian private signal from the sky, and a few minutes later a fleet of more than a hundred air-ships dropped down out of the darkness and hovered over what is now called the neutral ground between the Rock and Spain. One of these alighted at the signal station itself. It was the _Isma_, and within three minutes after she had touched the ground Alan was shaking hands with Alexis and asking him what brought him back so soon from the East. “I have come back because there is nothing much more to do there,” said Alexis. “Have you had any fighting here?” “Yes,” said Alan; “or, at anyrate, a big massacre.” And then he described what had befallen the Sultan’s expeditions. “Horrible but necessary, I suppose!” replied Alexis, not without a shudder at the news. “I have been doing my damage on land. I didn’t wait for the enemy to begin hostilities, so as soon as day broke we got to work. We have wrecked Ekaterinburg, Slatonsk, Orenburg, and Uralsk, and blocked the four roads into Russia from Asia. “The Tsarina’s Asiatic forces had concentrated there in large numbers ready to come into Europe. We found some air-ships intended to cover them, but we had the best of the elevation, and smashed them up. The slaughter has been something perfectly frightful. I had a hundred and fifty ships in action, and there isn’t a man left of the Asiatic troops that is not getting back to where he came from as fast as he can go.