discarded, as being utterly incompatible with the principles of the
military art. A writer, however, of some pretensions in this country,
recommends its adoption for the defence of Baltimore and the shores of
the Chesapeake. The same author would dispense entirely with our
present system of fortifications on the sea-coast, and substitute in
their place wooden Martello towers! This would be very much like
building 120 gun ships at Pittsburg and Memphis, for the defence of the
Ohio and the Mississippi rivers, and sending out duck-boats to meet the
enemy on the Atlantic!

In the second system, the works on the extreme frontier are to be placed
about thirty or forty miles apart, and those of the second and third
lines respectively thirty or forty miles in rear of the first and second
lines, and opposite the intervals.

In the third system, first recommended by Vauban and more recently by
Rogniat, the works are to be arranged in the same manner as in that of
D'Arçon, but the distance between them is to be from seventy to one
hundred miles, and each fort arranged for covering a large intrenched
camp.

Either of these last two systems is well suited to the defence of an
open frontier. The former is applied to the side of France towards
Belgium, and the latter, with certain modifications, to the defence of
Western Germany. The first line of fortifications on the northern
frontier of France consists of Dunkirk, Lille, Valenciennes, Condé,
Quesnoy, Rocroi, Charlemont, Mézières, and Sedan; the second line, of
Calais, Andres, St. Omer, Béthune, Arras, Douai, Chambrai, Landrecies,
and Avesnes; the third line, of Boulogne, Montreuil, Hesdin, Abbeville,
Amiens, Bapaume, Peronne, Ham, and Laon.