If the only work of a fleet were to defend one’s own harbors, then colonies, whatever might be their commercial importance, as an arm of naval strength, would be of but little value.  If all the use England had for her navy were to defend London and Liverpool, she would do well to abandon many of her distant strongholds, which have been won at such cost, and which are kept with such care.  If all our ships had to do were to keep the enemy out of Boston harbor and New York bay, it would not matter much, if every friendly port fifty miles from our own borders were closed against us.  But the protection of our own ports is not by any means the chief work of fleets.  The protection of commerce is as vital a duty.  Commerce is the life-blood of a nation.  Destroy that, and you destroy what makes and mans your fleets.  Destroy that, and you destroy what supports the people and the government which is over the people.  But if commerce is to be protected, war-ships must not hug timidly the shore.  They must put boldly out to sea, and be wherever commerce is.  They must range the stormy Atlantic.  They must ply to and fro over that primitive home of commerce, the Mediterranean.  Doubling the Cape, they must visit every part of the affluent East and of the broad Pacific.  With restless energy they must plough every sea and explore every water where the hope of honest gain may entice the busy merchantman.

See what new and trying conditions are imposed upon naval power.  A ship, however stanch, has her points of positive weakness.  She can carry only a limited supply either of stores or of ammunition.  She is liable, like everything else of human construction, to accidents of too serious a nature to be repaired on ship-board.  If, now, from any reason, from disasters of storm or sea, or from deficient provisions, she is disabled, and no friendly port be near,—­and in time of war no ports but our own are sure to be friendly,—­then her efficiency is gone.  And this difficulty increases almost in the ratio that modern science adds to her might.  The old galley, which three thousand years ago, propelled by a hundred strong oarsmen, swept the waters of the Great Sea, was a poor thing indeed compared with a modern war-ship, in whose bosom beats a power as resistless as the elements.  But its efficiency, such as it was, was not likely to be impaired.  It had no furnace to feed, no machinery to watch, only the rude wants of rude men to supply, and rough oars to replace.  A sailing ship, dependent upon the uncertain breeze, liable to be driven from her course by storms or to be detained by calms, gives no such impression of power as a steamship, mistress of her own movements, scorning the control of the elements, and keeping straight on to her destination in storm and calm alike.  But in some respects the weak is strong.  The ship is equal to most of the chances of a sea-experience.  If the spar break, it can be replaced.  If the storm rend the sails to ribbons, there are skilful