The circumstances of naval war have changed so much within the last hundred years, that it may be doubted whether such disastrous effects on the one hand, or such brilliant prosperity on the other, as were seen in the wars between England and France, could now recur. In her secure and haughty sway of the seas England imposed a yoke on neutrals which will never again be borne; and the principle that the flag covers the goods is forever secured. The commerce of a belligerent can therefore now be safely carried on in neutral ships, except when contraband of war or to blockaded ports; and as regards the latter, it is also certain that there will be no more paper blockades. Putting aside therefore the question of defending her seaports from capture or contribution, as to which there is practical unanimity in theory and entire indifference in practice, what need has the United States of sea power? Her commerce is even now carried on by others; why should her people desire that which, if possessed, must be defended at great cost? So far as this question is economical, it is outside the scope of this work; but conditions which may entail suffering and loss on the country by war are directly pertinent to it. Granting therefore that the foreign trade of the United States, going and coming, is on board ships which an enemy cannot touch except when bound to a blockaded port, what will constitute an efficient blockade? The present definition is, that it is such as to constitute a manifest danger to a vessel seeking to enter or leave the port. This is evidently very elastic. Many can remember that during the Civil War, after a night attack on the United States fleet off Charleston, the Confederates next morning sent out a steamer with some foreign consuls on board, who so far satisfied themselves that no blockading vessel was in sight that they issued a declaration to that effect. On the strength of this declaration some Southern authorities claimed that the blockade was technically broken, and could not be technically re-established without a new notification. Is it necessary, to constitute a real danger to blockade-runners, that the blockading fleet should be in sight? Half a dozen fast steamers, cruising twenty miles off-shore between the New Jersey and Long Island coast, would be a very real danger to ships seeking to go in or out by the principal entrance to New York; and similar positions might effectively blockade Boston, the Delaware, and the Chesapeake. The main body of the blockading fleet, prepared not only to capture merchant-ships but to resist military attempts to break the blockade, need not be within sight, nor in a position known to the shore. The bulk of Nelson's fleet was fifty miles from Cadiz two days before Trafalgar, with a small detachment watching close to the harbor. The allied fleet began to get under way at 7 A.M., and Nelson, even under the conditions of those days, knew it by 9.30. The English fleet at that distance was a