Russia, Austria, Prussia, Sweden, and other continental powers, have but little commerce to be protected, while their extensive frontiers are greatly exposed to land attacks: their fortifications and armies, therefore, constitute their principal means of defence.

But for the protection of their own seas from the inroads of their powerful maritime neighbor, Russia and Austria support naval establishments of a limited extent.

Russia has, in all, some one hundred and eighty vessels of war, and Austria not quite half that number.[13] [Footnote 13: These numbers include _all_ vessels of war, whether in commission, building, or in ordinary.] The United States possess no colonies; but they have a sea-coast of more than three thousand miles, with numerous bays, estuaries, and navigable rivers, which expose our most populous cities to maritime attacks.

The northern land frontier is two thousand miles in extent, and in the west our territory borders upon the British and Mexican possessions for many thousand miles more.

Within these limits there are numerous tribes of Indians, who require the watchful care of armed forces to keep them at peace among themselves as well as with us.