What defence would be possible against such missiles? Liable to be shattered from below, or shivered from above, the warship will be placed at an ever-increasing disadvantage. Its size will only render it an easier mark; its strength, bought at the expense of weight, will be but the means of insuring a quicker descent to the sea’s bottom. Is it not probable that sea-fights will become more and more matters of a few terrible, quickly-delivered blows? Human inventions will hold the balance more and more evenly between nations of unequal size, first on sea, then on land, until at last, as we may hope, even the hottest heads and bravest hearts will shrink from courting what will be less war than sheer annihilation, and war, man’s worst enemy, will be itself annihilated. SUBMARINE BOATS. The introduction of torpedoes for use against an enemy’s ships below the waterline has led by natural stages to the evolution of a vessel which may approach unsuspected close enough to the object of attack to discharge its missile effectively. Before the searchlight was adopted a night surprise gave due concealment to small craft; but now that the gloom of midnight can be in an instant flooded with the brilliance of day a more subtle mode of attack becomes necessary. Hence the genesis of the submarine or submersible boat, so constructed as to disappear beneath the sea at a safe distance from the doomed ship, and when its torpedo has been sped to retrace its invisible course until outside the radius of destruction. To this end many so-called submarine boats have been invented and experimented with during recent years. The idea is an ancient one revived, as indeed are the large proportion of our boasted modern discoveries. Aristotle describes a vessel of this kind (a diving-bell rather than a boat, however), used in the siege of Tyre more than two thousand years ago; and also refers to the divers being provided with an air-tube, “like the trunk of an elephant,” by means of which they drew a fresh supply of air from above the surface--a contrivance adopted in more than one of our modern submarines. Alexander the Great is said to have employed divers in warfare; Pliny speaks of an ingenious diving apparatus, and Bacon refers to air-tubes used by divers. We even find traces of weapons of offence being employed. Calluvius is credited with the invention of a submarine gun for projecting Greek fire. The Bishop of Upsala in the sixteenth century gives a somewhat elaborate description of certain leather skiffs or boats used to scuttle ships by attacking them from beneath, two of which he claims to have personally examined. In 1629 we read that the Barbary corsairs fixed submarine torpedoes to the enemy’s keel by means of divers.