Another fact gave basis for vague hope: a scrutiny of the whole horizon showed no answering signal. When Indians resort to such telegraphy, as they often do on the plains and among the mountains, there are calls and replies. It is on record that on one occasion the news of the signing of an important treaty at Washington affecting the Sioux was known to that tribe before the telegraphic messages could reach the army officers at the reservation. It was carried westward by Indian telegraphy which none of us fully understands, except that it seems to be through signal fires from elevated positions. But in that case, there must have been smoke or blaze visible at different points, as we know was really the case. But Alden Payne saw only the shadowy wisp of vapor in front of him, and must wait to learn its full meaning. That knowledge could not be long in coming. CHAPTER XVI CAUSE AND EFFECT Alden was convinced from a study of the signal smoke that it was gradually fading, as if the fire which caused it was not replenished. What this signified, as well as the meaning of the display itself, was beyond him. When the interval between him and the danger point had dwindled to an eighth of a mile, Dick did an almost incredible thing. Until then he had shown no sign of seeing the warning. Suddenly he stopped, raised his head, thrust his ears forward and looked steadily at the thin column of vapor for several minutes. The reins lay on his neck and the rider did not touch them. The animal wheeled abruptly to the right and broke into a gallop. His action showed that he read the signal smoke aright. Indians were there and he must avoid them. “I shall not interfere again with you,” said Alden admiringly; “you know a hundred times more than I do of these matters.” None the less, our young friend was uneasy. With all the pony’s sagacity, it would not have been strange if he was outwitted. The dusky enemies must have believed it was an experienced Express Rider who was coming from the east, and it would seem likely to them that he would direct his pony as the animal was now directing himself. If so, the precaution could hardly be of avail. The ground rapidly changed in character. Before Alden looked for it the incline increased, and he was riding among boulders, rocks and dwarfed pines. He felt a coolness too in the air, though the ridge did not rise anywhere near to the snow line. Looking down at the ground he saw no signs of others having passed the way before him. He was the pioneer in that dismal solitude. He was glad when the pony of his own accord dropped from the gallop to his rapid, graceful walk. It was impossible for him to progress in a straight line, and he was forever turning to the right or left, rarely following a direct course for more than a few rods.