"Here's as far as we can go, boys, until we get word from Mr. Tevis. There's the tree where I leave the messages." He pointed to a big oak that had been struck by lightning, and split partly down the immense trunk. One blackened branch stuck up. It had a cleft in it, in which a letter could be placed and seen from afar.
"Now I'll just leave a note there, and we'll have to be guided by what happens," Mr. Hardy went on.
He wrote something on a piece of paper, and asked Jack for the rings and the card symbol. These, with the message he had written, he placed in an envelope. The letter was enclosed in a bit of oiled silk, and the whole deposited in the cleft of the limb.
"It might rain before it is taken away," he explained. "You can never tell when Mr. Tevis or his messengers come. He can see that letter from his house, by using a telescope, but he may not send for it. It all depends."
"How will you know if he does?" asked Jack.
"I will come back here to-morrow at noon," replied the guide. "If there is an answer, there will be a little white flag where the letter was, Then I will know what to do."
There was nothing to do but wait. Mr. Hardy explained that it was necessary that they move back down the mountain, a mile or more away from the signal tree. To Jack and his chums this seemed a lot of needless precaution, but they were in no position to do anything different.
Jack passed the night in uneasy slumber, for he could not help thinking of what the morrow might bring and what effect it might have on his search for his father. But all things have an end, and morning finally came. After breakfast Mr. Hardy looked well to the saddle girths, as he said, if they were to go further on their journey, they would have to proceed over a rougher road than any they had yet traversed.
They started for the blighted oak so as to reach there about noon. How anxiously did Jack peer ahead for a sight of the lightning- blasted tree, in order to catch the first glimpse of the white flag he hoped to see! He was so impatient that Mr. Hardy had to caution him not to ride too fast. But in spite of this the boy kept pressing his horse forward. As the little cavalcade turned around a bend in the trail Jack cried out:
"I see it! There's the white flag! Now we can go on and hear the news of my father!"