The charted island. Previous history of the boys. The professor. Mysteries. The strange oars and ropes. Experiments. The various trips through the Island. Meeting the natives. The caves. Finding metals and ores. A strange village.

The Town of Unity. Enterprises on the island. Building a ship. Homesick. Considering the question of other islands. Treasure hunting. The Krishnos. Their beliefs and practices. The comparison of customs with the white people. Preparing to launch the vessel. The professor decides to remain. Angel. The message. Blakely. A scrap of paper with illegible words. The V-shaped tracing. Guessing the contents of the note.

Deciphering the discolored paper. The arrow on the sheet. The first Walter letter. The comparison. Dimensions of the vessel. The engine. The professor and John's error. Pointing to an island. Convinced of the correctness of the boys' views. Launching of the vessel. The feast day. Putting up the rigging. Selecting a crew. Preliminary trials. The day for departure. The trip to Valparaiso. Reshipping to New York. Telegrams home after three years. Angels and the wonders of New York. The great change in the boys. The return to Wonder Island. Reaching Valparaiso. Meeting Blakely. The new steamer. Installation of a line to Wonder Island. The return trip.

Steaming up Enterprise River. Unity in sight. The natives at the wharf. The enthusiasm. The chiefs witness the arrival. A "Grand Homecoming." The boys visit the natives. Contemplating voyages to discover other islands. Native sailors. Sutoto captain of the Pioneer. Rumors about the boys. Plans for the proposed trips. The force for the expedition. A cargo of copper. The trip to the copper treasure cave. Tides. Fireflies. Explanation of the light. Light without heat The problem of light. Advantages of light which generates no heat. Color of daylight. Phosphorescent glow. Catching fireflies. Scaling the heights. The spot where the Walter note was found. A skull with mysterious characters on it. The mark on the skull and the mark in the message. The star. Cryptic signs.

Sutoto at the top of the peak. The telescope. The view of Unity. The Illyas' village. The visit to the last captured village. The reception. The kindness of the chief. The