Why was it necessary to empty the gasoline from the tanks after Auguste Piccard's dive?

After Auguste Piccard's dive, it was necessary to empty the gasoline from the tanks because the gasoline served as a buoyancy aid during the descent. Once the dive was completed, the buoyancy needed to be adjusted to ensure safe ascent. Emptying the gasoline allowed for greater control over buoyancy and prevented potential hazards associated with the flammable substance at surface pressure. This procedure was critical for the safety and functionality of the submersible after its deep-sea exploration.