"And go you shall. I will write the necessary order. You have done well, and I understand you have some days of leave coming. To them I shall add more. But come back to me," he added, as he filled out the pass form. "Come back. We need you Americans now more than ever!"

"We'll come back," promised Tom. "All I want to go to Paris for is to find out about my father."

"Ah, I envy you," said the captain softly. "Both in the possession of a father, who must be proud to have such a son as you, and also because you are going to Paris. It is the most beautiful—the most wonderful—city in the world. And to think—to think that those barbarians would sack her! Ah, it is terrible!" and with a sad nodding of his head, following the shaking of an avenging fist toward the German lines, he waved Tom and Jack an adieu.

The two Air Service boys lost little time in making their preparations to leave for the French capital. They had to get certain passes and papers, and they wished to say good-bye to some of their comrades in arms. For, more than any other branch of the service, is aviation uncertain as to life or death. Tom and Jack well knew that some, perhaps many, of those who wished them "au revoir," and "bonne chance," would not be alive when they returned. And Tom and Jack might not return themselves. True, their chances were comparatively good, but the fortunes of war are uncertain.

And so, after certain preliminaries, Tom and Jack, their pet machines in the hangars, left behind their beloved comrades and were taken by motor to the nearest railway station. There they secured their tickets and took their places to wait, with what patience they could, their arrival in Paris.

The train was well filled with "permissionnaires," or soldiers on leave for a few days of happiness in the capital, and at certain stations, where more got on, the rush was not unlike that at a crowded hour in some big city.

"I see something good," remarked Jack, as they sat looking out at the scenery, glad, even for a brief moment, to be beyond the horrors of war.

"What?" asked his companion.

"There's a dining-car on this train. We sha'n't starve."

"Good enough, I almost forgot about eating," said Tom. "Now that you speak of it, I find I have an appetite."