THE FLYING MERMAID IN THE HOLLOW EARTH

What does an enterprising inventor do to follow up the marvelous dirigible-ship Monarch and an amazing submarine called Porpoise?

Why, cobble them together into an astounding vessel that travels on both air and sea, and then head straight into his wildest adventure yet -- more than twenty thousand leagues under the Earth

Along for the ride are his companions from the previous two Great Marvel books, teenagers Mark Sampson and Jack Sparrow, and the irrepressible Washington White. Lost race of giants? Killer plants? Deadly, bizarre creatures? Treasure beyond imaging? You bet.