Author(s): Percy Francis Westerman

History

This boys' adventure novel, originally published in 1912 is about a mysterious man from a South American country. He is an inventor, who has discovered a new kind of lighter-than-air gas that he called "helia", which is much lighter than helium or hydrogen. The inventor uses helia in many inventions, including back-packs that could help a man float in the air or fly upwards, and in the remarkable titular submarine that could, when enough helia was used, fly!