Louise, who had not wanted Linda to take the unknown course, had said nothing about the cause of the accident, for fear of hurting her chum's feelings. But Linda's mind had been busily working on the explanation ever since the tank went dry.
"Lou," she said finally, as they walked on through the darkness, "I think I have the explanation."
"What explanation? How to get out of these woods?"
"No, no. Of the reason why our gas ran out. I should have had enough to get to Syracuse. But do you remember hearing a plane land near to ours, while we were in the Convent?"
"Yes, of course. We both saw it."
"Well, do you know what I believe? I think that was Bess Hulbert, in the Flying Club's Moth—and it was she who was following us all the way to the Convent."
"Linda!" cried Louise, in amazement. "But how could she ever know we were here? Not that I'd put it past her—but how could she possibly find out, or guess what we were up to?"
"I don't know, except that she may have seen us—or our names on the hotel register at Plattsburg. People who are committing crimes are always on the watch, you know, expecting to be caught."
"How could she ever dump out our gas, in so short a time?"
"She didn't. She put a little hole in the gas tank, probably, so that the gas would leak out slowly. That would be a much meaner thing to do than to cut a strut, or injure the propeller, because either of those things would keep us from going up in the air without discovering it, and we wouldn't learn our danger from a leak without flying a while. Besides, whatever happened would happen when we were some distance away—so that she couldn't possibly be blamed! And it would be too late to do anything."