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.

Such, however, is not the case.  Improvements in the mode of attack have not kept pace with the facilities of locomotion; and, although fortifications do not now usually sustain a siege of as many days as in former times, still, as compared with the relative lengths of campaigns in ancient and modern wars, the proportional length of sieges is now even greater than formerly.  When the same is accomplished in a campaign of seven weeks as was formerly done in a war of seven years, it is not necessary that fortified places should hold out a very long time.  A place that can sustain a siege of a month is now deemed sufficiently strong for ordinary campaigns; for by the end of that time the defensive army will either be destroyed, or be able to come to its succor.  In either case a longer defence would not be required.

A reference to the most important sieges of the last century or two will show that forts are, on an average, capable of sustaining a siege for more than that length of time.  Lille, in 1708, held the allies in check for a whole year; and again, in 1792, compelled the Austrians to raise the siege after an unsuccessful attack of fifteen days.