But it was one thing to talk so confidently and quite another to accomplish the end they were striving for. They had not yet discovered a single one of the hidden wireless stations, and the secret of the dollar was still a secret. As far as the members of the wireless patrol could see, it was likely to remain a secret. How they could secure one of the dollars without being detected, they did not know; and how they were to read the message, even if they did get the dollar, was more than they could see; for by this time they had dropped the idea that the messages were engraved on the coins. More and more those dollars appeared a great and insuperable obstacle.
"Couldn't we manage to see the spy when he marks those dollars?" asked Roy. "Is there any way that we could get into his house and hide, so as to watch him?"
"You mustn't think of trying," said Captain Hardy decisively. "But possibly you could find a new place to watch from that would enable you to see him better. These field-glasses of mine are very powerful, and if you can find the proper view-point, you can see him well, even from a distance."
Without a word Roy grabbed his hat and darted out of the house. A second later he was slipping through the thicket on the sloping hillside. Cautiously he crawled from one point to another. The only station that gave any promise of success was the pine grove originally selected. The tree from which they had been watching the spy's house was a giant pine that towered above every other tree in the grove. But the scouts had never dared to ascend beyond the protecting foliage of the other trees, lest they be detected. So they had been looking upward at an angle, as they watched the spy's house. Roy now saw that if he were to climb high up in the big pine, he would be on a level with the spy's windows, and could doubtless see clearly into the house. The difficulty would be to make the climb without being detected.
Roy made his way back to headquarters and reported on his observations. "I didn't go up," he said, "for fear he would see me."
"You were wise," replied Captain Hardy. "We must devise some plan by which you can get up the tree unnoticed."
"Camouflage!" said Willie suddenly. "Fix one of us up like a pine tree. Then he won't see us."
"Just the idea," said Lew laughing.
"We'll have to use the smallest boy in the bunch," said Captain Hardy, "and that's you, Willie. Come. We'll see what we can do with you. Go get me some samples of pine bark and needles."
Willie speedily got the desired objects. Captain Hardy examined them critically. "You ought to have a dark brown suit, painted with irregular stripes, like branches, and dabs of green, like foliage."