Airplanes carry the mail
Airplanes in this country are chiefly used for carrying mail. "The mail must fly" is the slogan of the mailmen of the air, and in storm or fog—even in the face of a tornado—it has gone.
In May, 1919, a hydroplane belonging to the United States navy made the first trip across the ocean. A hydroplane is an airplane having a boat-like body so that it is able to alight on or rise from the water.
Transatlantic flights
In July a British dirigible flew across with its crew. A few weeks earlier a British plane flew from continent to continent in less than sixteen hours. It took Columbus seventy days to make his crossing.
JOHN P. HOLLAND, WHO TAUGHT MEN HOW TO SAIL UNDER THE SEA
Bushnell and Fulton and the undersea boat
211. The Submarine. During the War of the Revolution an American named Bushnell worked on the problem of making a boat that would sail under the surface of the sea. He was the first to work on this problem and is called the Father of the Submarine. Some years later Robert Fulton (page [257]) became interested in the submarine. In 1801 he built one for the French government. But Fulton turned his efforts to making steamboats and did not continue his plans for a successful diving boat.