Bartolomeu Lourenço de Gusmão was a Colonial Brazilian priest and naturalist who was a pioneer of lighter-than-air airship design. He is also one of the main characters in Nobel Prize-winning José Saramago's Baltasar and Blimunda.
Portrait of Bartolomeu de Gusmão by Benedito Calixto
An airship or dirigible balloon is a type of aerostat or lighter-than-air aircraft that can navigate through the air under its own power. Aerostats gain their lift from a lifting gas that is less dense than the surrounding air.
A modern airship, Zeppelin NT D-LZZF in 2010
Dirigible airships compared with related aerostats, from a turn-of-the-20th-century encyclopedia
U.S. Navy airships and balloons, 1931: in the background, ZR-3, in front of it, (l to r) J-3 or 4, K-1, ZMC-2, in front of them, "Caquot" observation balloon, and in foreground free balloons used for training
The air-filled red balloon acts as a simple ballonet inside the outer balloon, which is filled with lifting gas.