***
Over the following weeks, Cesare and his team used carefully constructed balloons to measure the lift of hot air versus hydrogen. They quickly determined hot air wouldn't be enough to float the airship. Even with hydrogen, they needed an enormous volume to lift a small weight. Armed with that information, Cal worked through her plans, cutting weight everywhere she could.
The boiler would be the biggest challenge. Train engines operated at much higher pressures than steamships, but to drive the airship any distance even they would be too heavy. The team struggled with spherical tanks as flaws in the shape became catastrophic much quicker than with cylinders. Cal started every time a boiler blew. Even the small prototypes made a considerable bang. She finally asked them to give her a
