After propounding his theory regarding hailstorms, Galien calculates how large an airship would have to be in order to transport an entire army with its equipment to Africa. His scheme was to construct a gigantic cubic vessel of good, strong canvas of double thickness plastered with wax and tar, covered with leather and reinforced in places with ropes and rigging; its edge was to be 1,000 toises (roughly 2,000 m), and each surface 1,000,000 sq. toises (approximately 4,000,000 m²) in area. In both length and breadth it would be larger than the city of Avignon, and would resemble a fair-sized mountain. It would carry 54 times as much weight as did Noah's Ark, and be capable of transporting an army with its artillery and provisions for a year.