He listened to the account of the lion hunt with interest.

“There are plenty of sportsmen in America,” he declared, “who would give a large sum for the sport you have just enjoyed, could they purchase it. You are fortunate.”

As nothing was to be gained by lingering longer in the vicinity, Frank caused the Dart to rise and the journey was resumed.

Once more the airship was speeding over the African wilds.

The next day they came in sight of a mighty lake.

“Albert Nyanza Lake!” declared Frank. “One of the sources of the Nile.”

Professor Gaston was much interested, and took notes of the event. Other lakes were crossed, and the Mountains of the Moon were sighted.

Then the airship bore away to the northeastward. It was Frank’s purpose now to reach the North Pole in the quickest possible time.

Days passed into weeks.

Still the Dart kept on across the Indian Ocean, over India, and the summits of the Himalayas.