"The reason that a hot-air balloon flies is that the hot air inside the balloon is lighter than the cold air outside the balloon. So, the balloon generates buoyancy, which enables it to lift off!" Mike was explaining airship design at his institute.
"We don't necessarily need to use hot air balloons. If we use another gas, a gas that is even lighter than air, we can do the same thing. I remember when I was at Akkad Alchemy College, some alchemists were looking for lighter gases than air. They wanted to use that to make airships!" he explained.
Mike's institute, which was aptly named the Mike Alchemy Institute, specialized in the manufacturing of airships. Akkad Alchemy College had carried out this experiment a long time ago, but in the end, it had failed.