This tale makes no claim to the character of an exhaustive illustration of all that belongs to the art of diving. It merely deals with the most important points, and some of the most interesting incidents connected therewith. In writing it I have sought carefully to exhibit the true and to ignore the false or improbable.

I have to acknowledge myself indebted to the well-known submarine engineers Messrs Siebe and Gorman, and Messrs Heinke and Davis, of London, for much valuable information; and to Messrs Denayrouze, of Paris, for permitting me to go under water in one of their diving-dresses. Also—among many others—to Captain John Hewat, formerly Commander in the service of the Rajah of Sarawak, for much interesting material respecting the pirates of the Eastern Seas.

R.M.B. Edinburgh, 1876.