Robinson and Fritz explore the cliffs that flank their camp on one side, searching for “a passage through this barrier” (127). The cliffs cut them off from the rest of the island, and Robinson is eager to discover what lies beyond. Their expedition reveals a grove of rubber trees—about which Robinson says, “Wouldn’t it be nice to have rubber boots and shoes?” (129)—as well as a cluster of beetle larvae which they roast and eat with a side of potatoes. The next morning, they make candles from a type of small, waxy berry, and, for the first time, the family enjoys light after sundown.

The Robinsons spend the next six weeks fortifying their cache of supplies at the beach, planting hedges and thorny bushes around it, and mounting two cannons on the hill overlooking the stream. In desperate need of new clothes, Robinson, Fritz, Ernest, and Jack make a final trip to the wrecked ship, stripping it of every last useful item, including the crews’ clothing. With all they can carry loaded on the pinnace, they set a charge and blow up the ship.

The following day, the entire family sets out to explore the territory along the cliffs.