This document discusses the history and development of hot air balloons and gas balloons. It describes some early experiments with hot air balloons and notes that the first person to fly in a hydrogen balloon reached an altitude of 9,000 feet. It then discusses how balloons were later used for various purposes like delivering mail, exploring the atmosphere, and in wartime for activities like searching for submarines. The document concludes by stating that balloons went on to play an important role in everyday life.