2. Those who believe that submarines will revolutionise warfare, ocean locomotion, marine industries, &c., and that an epoch may come in which merchantmen will alone sail the ocean and all the warships will be submarines or submersibles. 3. Those who recognise that the submarine boat of to-day is a great improvement on the boats of twenty years ago; who believe that although at present it suffers from grave defects, its development will continue, and who are of opinion that it will find useful spheres of action in time of war. Much of the adverse criticism which the “submarine boat” has had to encounter has been due to the popular belief that this type of craft was intended to do its work _below_ the surface of the water. As it is impossible at present to see beneath the waves, many critics have declared the submarine to be a perfectly useless fighting vessel. It cannot be too often asserted, for the sake of overcoming prejudice, that the proper place of the submarine is _at the surface_, and that she only goes below for short intervals. This is now universally recognised by constructors of such craft, which it might be more correct to term “submersibles” or “diving torpedo-boats.” So far back as 1886 Mr. Nordenfelt remarked, “It is impossible to think of a submarine boat that actually manœuvres and does its work under water. I gave that up from the very commencement.” By the term “submarine” we mean to imply a vessel capable of manœuvring on the surface like an ordinary torpedo boat, of running awash with her conning tower alone above water to enable her to be steered, and of totally immersing herself for short periods either to escape detection, avoid the fire of the enemy, or fire torpedoes. The history of the submarine bears a curious resemblance to that of the torpedo and the torpedo vessel in many particulars. All three have been declared to be the weapons of the weaker power and of no possible value to a nation which must maintain the command of the seas. The first Whitehead torpedoes were certainly slow and erratic; now they are capable of running within a few inches of the required depth at a speed of over 37 miles an hour for a range up to 2,000 yards, and hitting the point aimed at with almost the same precision as a gun. In spite of the sneers of fossilised officials, Great Britain adopted the torpedo-boat, and in the process of time evolved the destroyer, an offensive weapon of no mean value, and a type of craft which some have declared to be the fighting vessel of the future. She will soon be in the possession of nine under-water vessels, and it may be that the submarines of twenty years hence will bear the same resemblance to those of to-day, as the _Albatross_ does to the _Lightning_ of 1877.