"But you mustn't do that unless you have to," Will cautioned, "because, the minute the cry is heard, everybody within eighty rods would know what's going on. Have you matches with you?"
The boy felt in the pockets of his coat and nodded.
"Well, then," he said, "if you want to signal, wet your hands and rub the phosphorus off the matches. Turn your hands, palms in our direction, so no one can see from the other side and wig-wag."
"That will be fine!" exclaimed Jimmie. "I've got this wig-wag system down pat. I guess this Boy Scout training is pretty poor, ain't it, eh? The darker it is, the better we can talk!"
Jimmie darted away, while Will and Elmer remained stationary for a short time in order to give him an opportunity to get out of the range of their lights. Directly they heard him whispering back and listened.
"There's another stone cairn here!" he said. "I guess I knocked it over, for I can't tell exactly what it is. You can learn that when you come up with your searchlights! I think there are three stones."
"All right!" Will whispered back.
When the boys came to the spot from which tha voice had been heard they found three stones lying side by side on the floor of the gangway. It was plain that they had been placed one on top of the other, and so they accepted them as another warning of danger.
"I wish we had some intimation of the kind of trouble we are likely to get into," Elmer suggested, as they passed along. "I don't like this idea of boring a hole in the darkness with a little bit of a light and anticipating an attack at any minute."
"I don't like it a little bit myself," replied Will.