Nuovo trattato sulla vera rettificazione del circolo misurato esattamente con il diametro

Part 4, "Dissertazione sul modo di navigare sott' acqua" (Dissertation on a way to navigate underwater) includes a description of a simple submarine invented by the author, along with its various potential uses, including prolonged submersion and military confrontation. One folded plate includes an etching that shows a model of the submarine underwater, clearly illustrating both its means of propulsion (oars), and its ability to both carry and fire artillery.