However, because nitrogen is only 3% lighter than air, it is not an obvious choice for a lifting gas.

Ammonia has sometimes been used to fill weather balloons as a lifting gas.

The first lifting gas used was hydrogen, although this had well-known concerns over its flammability.

When the lifting gas was thus heated, it began to expand.

There is plenty of material for making the lifting gas.

The Germans had extensive experience with hydrogen as a lifting gas.

But the damage to hydrogen's reputation as a lifting gas was already done.

The savings do not only concern the lifting gas in itself.

The blimp's shape is maintained by the internal pressure of the lifting gas.

The gaseous state of water is lighter than air, and has successfully been used as a lifting gas.