By heating hydrogen balloons, large masses can be suspended underneath at roughly Earth gravity.

A few teenagers claimed to have witnessed his work, reporting that he had caused the blocks of coral to move like hydrogen balloons.

They found a shiny object there - a bomb attached to a hydrogen balloon made of rice paper.

The sphere sailed over to him like a hydrogen balloon.

The empty balloon weighs a little less than the hydrogen balloon, and so has a greater net lift.

It will also be a rare opportunity to witness the silent magic of six hydrogen balloons drifting away.

Site with information about the balloon attempt and a model of the hydrogen balloon.

A hydrogen balloon also freed her from having to tend a fire to keep the craft airborne.

"Photo" - Take and develop a photograph, and deliver it by hydrogen balloon.

This so enthused Franklin that he subscribed financially to the next project to build a manned hydrogen balloon.