The morale of tradition is a curious thing, and often will nerve a sword arm when the most impassioned utterance of a beloved leader may fail. There were few among the soldiers of France who forgot that in the south of this same plain of Champagne-Pouilleuse was the home of Joan of Arc, the Maid of Orleans, patriot and saint, and more than one French soldier prayed that the same voices which had whispered in the ear of the virgin of Domremy should guide the generalissimo who was to lead the armies of France upon the morrow. Here, tradition again found old alliances severed and new ones formed, for the Maid of Orleans led the French against the English, while in the serried ranks awaiting the awful test of the shock of battle, English and French soldiers lived and slept as brothers. The topography of the region of the battle field is of more than common interest, for modern tactics deal with vaster stretches of country than would have been considered in any previous war. This is due, partly, to the large armies handled, partly to the terrific range of modern artillery, and also to what may be called the territorial perceptiveness which aeronautical surveys make possible to a general of to-day. While war has not changed, it is true that a commander of an army in modern campaign is compelled to review and to take into account a far larger group of factors. A modern general must be capable of grasping increased complexities, and must possess a synthetic mind to be able to reduce all these complicating factors into a single whole. The first factor of the battles of the Marne was the topographical factor, the consideration of the land over which the action was to take place. Let the River Marne be used as a base from which this topography can be determined. The Marne rises near Langres, which is the northwest angle of that pentagon of fortresses (Belfort, Epinal, Langres, Dijon, and Besancon), which incloses an almost impregnable recuperative ground for exhausted armies. From Langres the Marne flows almost north by west for about fifty miles through a hilly and wooded country, then, taking a more westerly course, it flows for approximately seventy-five miles almost northwest, across the Plain of Champagne, past Vitry-le-Francois and Chalons, thence almost due westward through the Plateau of Sezanne, by Epernay, Chateau Thierry, La Ferte-sous-Jouarre, and Meaux to join the Seine just south of Paris. In the neighborhood of Meaux, three small tributaries flow into the Marne--the Ourcq from the north, and the Grand Morin and Petit Morin from the east. The Marshes of St. Gond, ten miles long from east to west and a couple of miles across, lie toward the eastern borders of the Plateau of Sezanne, and form the source of the Petit Morin, which has been deepened in the reclamation of the marsh country.