A little later the four Bobbsey twins were at the place where the brook splashed noisily over a ledge of rocks, falling a distance of about two feet. It made a fine place to set up a water wheel, and Bert was soon fastening his in place so the falling stream would turn the paddles. If these worked he intended connecting them by means of a string belt and pulleys to a fan set up some distance away. But he had yet to build the fan.
Bert drove into the earth bank on one side of the little waterfall some pieces of wood to which he intended fastening his water mill paddle. He had finished this and was about to set up the wooden wheel when Flossie gave a startled cry.
Though he knew he had left his little sister sitting safely on the bank some distance away from the water, Bert felt that she might have gone too near the edge and might be sliding in.
“Look out!” he cried, dropping the wheel and turning around. Before he knew it, he set one foot on a slippery place on the bank. The next instant Bert felt himself sliding down toward the deep pool below the falls.
“Here I go!” he shouted wildly.
Bert could swim. Still, he did not want to fall in if he could help it, and he clutched desperately at the grassy bank.
CHAPTER XV
IN THE APPLE ORCHARD
“Bert! Bert! Hold on!” screamed Nan.
“I—I am holding on—all I can!” her brother answered.