Grabbing up a rifle, which example Bob and Ned imitated, Jerry ran in the direction of the voice. The noise made by the monkeys increased, and there were sounds as if a bombardment of the forest was under way.
“Where are you?” called Jerry. “We are coming!”
“Under this big rock!” called the professor, and the boys, looking in the direction his voice came from, saw the naturalist hiding under a big ledge of stone that jutted out of the side of a hill in a sort of a clearing.
“Can’t you come out?” called Ned.
“I tried to several times, but I was nearly killed,” replied the professor. “The monkeys are after me. Look at the ground.”
The boys looked and saw, strewn in front of the shallow cave in which the professor had ensconced himself, a number of round, dark objects. As they looked there came a shower of others through the air. Several of them hit on the rock, broke, and a shower of white scattered all about.
“What in the world are they?” asked Bob.
He ran toward the professor. No sooner had he emerged out of the dense forest into the clearing than a regular hail of the round objects fell all about him. One struck him on the shoulder and the boy was glad enough to retreat.
“What’s it all about?” asked Ned.