"Oh, I was wise enough to register the letter," Tom told him; "so I know it was safely delivered. Like as not he's taking his own time to answer, because sailings are not frequent in these days of submarine horrors. They never advertise what day the boat is expected to leave, always informing would-be passengers to be aboard at a certain time, although the vessel may remain in the harbor for another day or two. All that is done to prevent spies from sending by wireless information connected with the sailing to the other side, and which in turn would be communicated to the waiting U-boats."
There was a ring of the bell.
"That was the postman, Tom. I wonder now if he had anything for you," remarked Jack, who chanced to be sitting near the window where he could look out and observe all that was taking place in the street.
"I'll go down and see," his chum remarked, jumping up hurriedly; and Jack noticed that Tom, usually so composed and cool, was showing the effect of his late nervous strain in flying, now supplemented by this fresh cause for anxiety.
Tom returned in a few minutes. He held an open letter in his hand. One look Jack took at his beaming face, and then he too jumped hastily to his feet.
