53 Under the Yellow Sea; or, Frank Reade, Jr.’s Search for the Cave of Pearls.
54 From the Nile to the Niger; or, Frank Reade, Jr. Lost in the Soudan.
55 The Electric Island; or, Frank Reade, Jr.’s Search for the Greatest Wonder on Earth.
56 The Underground Sea; or, Frank Reade, Jr.’s Subterranean Cruise.
57 From Tropic to Tropic; or, Frank Reade, Jr.’s Tour With His Bicycle Car.
58 Lost in a Comet’s Tail; or, Frank Reade, Jr.’s Strange Adventure With His Air-ship.
59 Under Four Oceans; or, Frank Reade, Jr.’s Submarine Chase of a “Sea Devil.”
60 The Mysterious Mirage; or, Frank Reade, Jr.’s Desert Search for a Secret City.
61 Latitude 90 Degrees; or, Frank Reade, Jr.’s Most Wonderful Mid-Air Flight.
62 Lost in the Great Undertow; or, Frank Reade, Jr.’s Submarine Cruise in the Gulf Stream.