When was scuba first invented?
1943: Jacques Cousteau and Emile Gagnan invented and made an open‑circuit diving breathing set, using a demand regulator which Gagnan modified from a demand regulator used to let a petrol‑driven car run on a big bag of coal‑gas carried on its roof during war me shortages of petrol. Cousteau had his first dives with it.
Who invented air tanks?
15th century: Leonardo da Vinci made the first known mention of air tanks in Italy: he wrote in his Atlantic Codex (Biblioteca Ambrosiana, Milan) that systems were used at that time to artificially breathe under water, but he did not explain them in detail.