1 86 THE NEW WORLD OF SCIENCE 



for additional data and demands for new editions. It needs 

 no special insight to understand that a complete description of 

 the railway system of a country might enable an intelligence 

 officer to interpret isolated reports from spies in that country 

 regarding troop trains observed by them at different points, and 

 thus to construct an accurate picture of enemy troop move- 

 ments then taking place. The value to airplane bombing 

 squadrons of geographic descriptions of the vital economic 

 points in enemy territory, is manifest. The reader may him- 

 self imagine many other advantages which a full geo- 

 graphic knowledge of enemy territory would give to army 

 commanders. 



But the preparation of geographic monographs by no means 

 measures the full service which the Commission de Geographic 

 rendered during the war. High officers of the army appealed 

 to it for geographical information on a variety of problems. 

 Prior to the Aisne offensive they asked the Commission for 

 detailed data regarding the character of the river and its val- 

 ley floor, the nature of the soil, number of bridges, possible 

 locations for new bridges and the nature of the river banks 

 at such localities. They also required a special report on the 

 quarries occupied by the Germans, their depth, best ways of 

 entering them, and particularly which ones of the underground 

 quarries were provided with a surface covering of a thickness 

 and quality which would enable heavy artillery to crush in 

 the roofs by bombardment. On another occasion they asked 

 for a report on the Roumanian and Russian fronts as regards 

 conditions of marshes, rivers, soil, and roads, in the spring of 

 the year, in order that the high command might determine the 

 advisability of a great spring offensive. In these and many 

 other ways the Commission de Geographic of the Service Geo- 

 graphique contributed valuable aid to the prosecution of the 

 war. 



If it be true that an army fights on its maps, it is also true 

 that during the latter part of the war the Allies fought on 

 geographic models. The section of the Service Geographique 



