Let us notice how France has attempted to accomplish this object. The Mediterranean frontier has Fort Quarre, Fort St. Marguerite, St. Tropez, Brigancon, the forts of Point Man, of l'Ertissac, and of Langoustier, Toulon, St. Nicholas, Castle of If, Marseilles, Tour de Boue, Aigues-Montes, Fort St. Louis, Fort Brescou, Narbonne, Chateau de Salces, Perpignan, Collioure, Fort St. Elme, and Port Vendre. Toulon is the great naval depot for this frontier, and Marseilles the great commercial port. Both are well secured by strong fortifications. The Atlantic frontier has Bayonne; the forts of Royan, Grave, Medoc, Pate, &c., on the Gironde; Rochefort, with the forts of Chapus, Lapin, Aix, Oleron, &c., to cover the roadstead; La Rochelle, with the forts of the Isle of Re; Sables, with the forts of St. Nicholas, and Des Moulines, Isle Dieu, Belle Isle, Fort du Pilier, Mindin, Ville Martin; Quiberon, with Fort Penthievre; L'Orient, with its harbor defences; Fort Cigogne; Brest, with its harbor defences; St. Malo, with Forts Cezembre, La Canchee, L'Anse du Verger, and Des Rimains; Cherbourg, with its defensive forts and batteries; Havre, Dieppe, Boulogne, Calais, and Dunkirk. Cherbourg, Brest, and Rochefort, are great naval depots; and Havre, Nantes, and Bordeaux, the principal commercial ports. Many of the works above enumerated are small in extent and antiquated in their construction, and some of them quite old and dilapidated nevertheless, they have heretofore been found sufficient for the defence of the naval depots and commercial seaports of France against the superior naval forces of her neighbor. Omitting for the present all discussion of sea-coast defences, let us examine more particularly the character and influence of fortifications on land frontiers. All military writers agree that fortifications have heretofore exerted a great, and frequently a decisive, influence on the operations of a war. Those of France are frequently referred to as proofs of this influence. But, while all are disposed to allow that these works contributed much in former times to the defence of states, yet some have said that modern improvements in the mode of attack have rendered forts far less valuable than formerly.