Just before dark a terrific thunder-shower sprang up with all of the suddenness of such equatorial storms, and Bob and Paul made for the field as fast as their legs could carry them.  They sprang inside of the Sky-Bird's cabin, wet to the skin, where John and Tom were already ensconsed, and Grandpa the monkey gave them a noisy and hearty welcome. A little later, with the rain pattering heavily down upon the roof, all hands turned in for the first ground sleep they had had since starting out upon their trip.