"The contrary valves are made so that the one that opens outside is used for sending out the hot air, and after the removal of this hot air, it cannot by any means return backward. And this issues through window M, which closes with valve B. The fresh air is
drawn into the bellows through window N, and once it has entered into the bellows, valve A closes, and it can never go out again through this window. But when it has been heated, it returns out through the other window, M, as was said before."
Leonardo drew the mask for a diver joined by means of two reeds to a floating device in the form of a diving bell, which he called “bellows" The reed hoses for breathing are joined using joints covered by a double layer of leather, and a spiral of iron inserted into the joints prevents them from being crushed by the water pressure. The reeds come out to the surface and are supported and protected by a floating bell-shaped device. The small dome, with a hole in the upper part, conducts air through the hoses that arrive to the diver from the bottom of the floating device. One reed carries oxygen to the diver, while the other expels the already breathed air.
The model is based on the drawings:
- Codex Arundel f. 24 v. (1508)
London, British Library
- Codex Atlanticus f. 647 v. (1508)
Milano, Biblioteca Ambrosiana