"Why, what's the matter, Bruno?" cried Harry. "I never saw you act like this before."
"I believe he is scared," said Lawrence. "Andrew Jackson! Bruno scared!"
"I never knew him to be scared," said Harry, "but I believe he is. See how he trembles."
Before an investigation could be made, the horses began to rear and plunge, and the sentinels called out they were breaking loose.
"See to the horses," shouted Lawrence.
The men were just in time, as several of the horses had broken their halters. As it was, they had hard work to keep them from getting away.
"The horses are badly frightened. They are trembling like leaves," said the men.
"It must be some wild animal," said Lawrence. "Men, stay by the horses; Dan, Harry and I will investigate."
Lawrence took a burning brand from the fire, and all three, well armed, started to find the cause of the trouble. Bruno at first hung back, but when he saw Harry start, he followed; but it was noticed he kept close to his master's side.
The dog kept looking to the cliff back of their encampment. A large tree grew close to the cliff, and an animal could spring into it from the cliff. Cautiously the three men advanced.