Tom tried to be cheerful and to look for the best, but it was hard work. The tank was his pet invention, and, moreover, that her secrets should fall into the hands of the enemy and be used for Germany and against the United States eventually, made the young inventor feel that everything was going wrong.
The rain kept up all night, and this would make it correspondingly hard for them to pick up the trail in the morning.
"The only thing we can do is to make inquiries," decided Tom. "Fortunately, the tank can't easily be hidden."
They started off after an early breakfast. The roads were so muddy and wet that traveling was difficult and dangerous for the automobile, and they were disappointed in finding no one who had seen or heard the tank pass up to a point not far from the hotel where they had stayed overnight. From then on the big machine seemed to have disappeared.
"I know what they've done," Tom said, when noon came and they had found no trace of the ponderous war machine. "They've left the road and taken her cross country, and we can't find the spot where they did this because the rain has washed out the marks. Well, there's only one thing left to do."
"What's that?" asked Ned.
"Get the Hawk! In that we can look down and over a big extent of country. That's what I'll do—I'll phone for the airship. The rain is stopping, I think."
The rain did cease by the time one of Tom's men brought the speedy aircraft to the place named by the young inventor in his telephone message. There were still several hours of daylight left, and Tom counted on them to allow him to rise in the air and look down on the tanks possible hiding place.
"One thing's sure," he told Ned: "I know the limit of her speed, and she can't be farther off than at some place within a circle of about one hundred and twenty-five miles from my house. And it's in the direction we're in. So if I circle around up above, I may spot her."
"I hope so," murmured Ned.