Natural philosopher John Wilkins’ Mathematical Magick of 1648 contains a startling passage in which he foretells the advantages of a long-range submarine, or “ship, wherein men may safely swim underwater”: ‘Tis private; a man may thus go to any coast of the world invisibly, without being discovered or prevented in his journey; ‘Tis safe; from the uncertainty of Tides, and the violence of Tempests, which do never move the sea above five or six paces deep. From Pirates and Robbers which do so infest other voyages; from ice and great frosts, which do so much endanger the passages toward the...