method of communication when in flight without unduly straining the voice. It was very similar to a wireless telephone outfit which Tom and Jack had employed not long back, and by the use of which they could actually talk with an operator similarly equipped, even if standing on the earth a mile below their plane. It was arranged for all three of them, and could be removed from the head when no communication was desired. In the beginning they were not in the mood to make use of this contrivance, which, however, would undoubtedly be welcome later on, when they would be passing over the apparently limitless sea and the monotony had begun to wear upon their nerves. Then conversation might relieve the tension. It was Jack who presently called out: "I can see lights below us. Do you think we've crossed the Channel, Lieutenant?" "Yes, that's the English shore, and doubtless Dover lies directly below us, although we're at such a height that it's impossible to make sure." "What's the idea of keeping so high, Lieutenant?" continued Jack. "Simply to avoid collision with any of the coast guard fliers, who might take us for Huns meaning to attack London again after a long break. But Jack, I'm going to ask a favor of you." "Go to it then!" called out the other, who was plainly "on edge" with excitement over the wonderful fact that they were at last on their way. "Drop that formality from this time on," said Beverly earnestly. "Forget that I happen to rank you, for I'm sure your commissions are only delayed in the coming. From now on let it be either plain Colin, or if you prefer, Beverly. We're three chums in a boat--a ship of the air, to be exact--and all ranking on a level. You'll agree to that, won't you, Jack?" "You bet I will, Colin, and it's just like you to propose it!" cried the pleased Jack. After that they fell silent again, though now and then Jack, who was making good use of the night-glasses, announced that they seemed to be passing over some city. Tom had studied their intended course so thoroughly that he was able to tell with more or less accuracy what some of those places were. In so doing he always kept in mind the probable speed at which the big plane was traveling. They had veered a little, and would not come anywhere near Liverpool or