“That’s what Dad told us. He said it was along the right of way near the State road. Jackley was a section hand or signalman, or something.”

The land along the right of way was thickly wooded. It was an attractive part of the country and here and there the wooded spaces were broken by green fields and meadows. The boys were at the top of a slope, and they had a view of a wide expanse of country below them.

In the far distance, along the tracks, they could see a little red railway station, and back of that the roofs and spires of a village. Nearer still they could see the spindly legs and squat bulk of a water tank, painted a bright scarlet. This water tank was not far from the railway station, but half a mile down the track, and only a few hundred yards from the place where the Hardy boys were seated, rose the bulk of another water station.

But this tower⁠—one of the old style built before the modern tanks came into use⁠—was not freshly painted. It had been allowed to fall into a state of disrepair. Some of the rungs were missing from the ladder that led up the side, and the tower itself had a forlorn and weather-beaten aspect, as though it had been deserted. This, indeed, was the case. The new tower tank closer to the station had been erected to replace it, and although the old structure had not been torn down, it was not now used.

Frank took a huge bite out of his sandwich and began to munch it thoughtfully. The sight of the two water stations had given him an idea, but at first it seemed to him to be too absurd for consideration. He was wondering whether he should mention it to his brother.

Then he noticed that Joe, too, was gazing thoughtfully down the railway tracks. Joe raised a sandwich to his lips absently, essayed a bite and missed the sandwich altogether. Still he continued gazing at the two water towers.

Finally Joe turned and looked at his brother.

In the eyes of both was the light of a great discovery. They knew that they were both thinking of the same thing.

“Two water towers,” said Frank slowly.

“An old one and a new one.”

“And Jackley said⁠—”

“He hid the stuff in the old tower.”

“He was a railwayman.”

“Why not?” shouted Joe, springing to his feet. “Why couldn’t it have been the old water tower? He used to work around here.”

“He didn’t say the old tower of Tower Mansion, after all. He just said ‘the old tower!’ ”

“Frank, I believe we’ve stumbled on the clue!”

“It would be the natural thing for him to come to his old haunts after the robbery. And if he found he couldn’t get away with the stuff he would hide it somewhere he knew. The old water tower! Why didn’t we think of it before, Joe? Why, that must be the place!”