and fifty vessels,[13] carrying about nine thousand guns and thirty thousand men.  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.  Our authorized military establishment amounts to 7,590 men, and our naval establishment consists of seventy-seven vessels of all classes, carrying 2,345 guns, and 8,724 men.[14] This is certainly a very small military and naval force for the defence of so extended and populous a country, especially one whose political institutions and rapidly-increasing power expose it to the distrust and jealousy of most other nations.

[Footnote 14:  Since these pages were put in the hands of the printer, the above numbers have been nearly doubled, this increase having been made with special reference to the present war with Mexico.]

The fortifications for the defence of our sea-coast and land frontiers will be discussed hereafter.[15]

[Footnote 15:  Jomini’s work on the Military Art contains many valuable remarks on this subject of Military Polity:  also the writings of Clausewitz, Dupin, Lloyd, Chambray, Tranchant de Laverne, and Rudtorfer.  Several of these questions are also discussed in Rocquancourt, Carion-Nisas, De Vernon, and other writers on military history.  The several European Annuaires Militaires, or Army Registers, and the French and German military periodicals, contain much valuable matter connected with military statistics.]

CHAPTER VII.

SEA-COAST DEFENCES.