Mr. Henderson’s notes say:
Enclosed are some photos of a scratch built Japanese Fugo Fire Balloon, an area of interest that I’ve had for a long time, and I do have some original pieces of some in the collection. One of a kind model, built by a friend of mine. The balloon is 5″ in diameter. The scale is 1 to 500. Balloons were released from Japan, and used the Trade Winds to bring them across the USA and Canada. Some reached Ontario from the West Coast. Use Google for additional information on the actual use of the “Secret Weapon”.