Here, too, these young Air Service boys again found an opportunity for proving their worth in the rescue of pretty Bessie Gleason and her mother from an old chateau in Lorraine where Carl Potzfeldt, a German spy, had them imprisoned. These interesting and exciting events will be found in the second volume of the series, entitled: "Air Service Boys Over the Enemy's Lines; or, The German Spy's Secret."
Then came another series of happenings that must always appeal to boy readers fond of thrilling scenes, for in the next book, among many other things, is told how Tom and Jack succeeded in silencing the monster cannon that from a distance of sixty miles and more was bombarding Paris. That will be found narrated in "Air Service Boys Over the Rhine; or, Fighting Above the Clouds."
Then there is the volume just preceding this, in which again the two brave young Yankee air pilots were given an opportunity to prove the value of their training, now in the service of the American forces, for General Pershing had come across the sea, and his army was beginning to make its presence felt at several sectors of the battleline.
What they saw and did, as well as vivid descriptions of the momentous events accompanying the great German drive is told in the fourth book of the series, "Air Service Boys in the Big Battle; or, Silencing the Big Guns."
Among their friends at the front was a young and daring aviator, Harry Leroy by name, who had had the misfortune to be shot down behind the German lines, and it was in connection with his discovery and rescue by the chums that some of the events of the last volume came about.
And it may as well be confessed here that Tom felt more than a passing interest in the pretty sister of Harry, for Nellie Leroy was serving her country as a Red Cross nurse, being just then in one of the American field hospitals to which the wounded were being carried day after day while the Argonne drive was on.
Tom was a full hour and more reading his letters, rereading them, and dreaming over them. After their rescue from the château Mrs. Gleason and Bessie had gone to Paris, where the mother, ably assisted by her daughter, had thrown herself into Red Cross work. Now, so Bessie's note told Tom, her mother was very tired and the two had gone down to Nice for a brief rest. It would be perfect, Bessie wrote, if only Tom and Jack and Nellie Leroy were with them.
For a while Tom lost himself in the thought of being at Nice, by the blue sea, with Mrs. Gleason and Bessie and Nellie—especially Nellie—and with Jack. With Jack! That thought aroused him.
Still no Jack! He grew more and more concerned, and began to picture all sorts of grievous things as having happened to his chum.
Several times he thought he heard the well known voice near by, but on each occasion discovered that he had deceived himself. Tom felt he could stand it no longer, and had even commenced to set forth when, to his delight, he discovered Jack coming.