About half an hour after they had passed what had once been the jealously-guarded Russian frontier, a dazzling gleam of light suddenly blazed down from the black darkness overhead, and Olga, who was sitting by one of the windows of the car, bent forward and said-- “Look there! What is that? There is a bright light shining down out of the clouds on the train.” Alan saw the flash across the window, and, without even troubling to look up at its source, said-- “Oh, I suppose that’ll be the air-ship that was ordered to meet us at St. Petersburg. You know, we usually have one of them in attendance, when we trust ourselves alone among our possible enemies of the outer world.” The last sentence was spoken with a quiet irony, which brought home both to Olga and Serge the not very pleasant conviction that their previous conversation had by no means been forgotten. Serge, perhaps fearing to give utterance to his thoughts, remained silent, but Olga looked at Alan with a half-saucy smile, and said almost mockingly-- “Your Majesties of Aeria may well esteem yourselves impregnable, while you have such a bodyguard as that at your beck and call. I suppose that air-ship would not have the slightest difficulty in blowing this train, and all it contains, off the face of the earth at a moment’s notice, if it had orders to do so?” “Not the slightest,” said Alan quietly. “But in proof of the fact that it has no such hostile intentions, you shall, if you please, take a voyage beyond the clouds in it the day after to-morrow, from St. Petersburg.” “What!” said Olga, her cheeks flushing and her eyes lighting up at the very idea of such an experience. “Do you really mean to say that you would permit a daughter of the earth, as I am told you call the women who have not the good fortune to be born in Aeria, to go on board one of those wonderful air-ships of yours, and taste the forbidden delights of spurning the earth and sharing, even for an hour, your Empire of the Air?” “Why not?” replied Alan, with a laugh. “What harm would be done by taking you for a trip beyond the clouds? We are not so selfish as all that; and if the novel experience would give you any pleasure, we have a perfect right to ask you to enjoy it. Will you come?” “Surely there is scarcely any need for me to say ‘yes.’ Why, do you know, I believe I would give five years of my life for as many hours on board that air-ship of yours,” said Olga; “and if you will do as you say, you will make me your debtor for ever. Indeed, how could a poor earth-dweller such as I am repay a favour like that.” “Ah, if only you were an Aerian, I should not have much difficulty in telling you how you could do that,” retorted Alan, with almost boyish candour. “As it is, I am afraid I must be satisfied for my reward with the pleasure of knowing that I have given you a pleasurable experience.”