than the last; it can scarcely, at this intensive pace, be less costly.
Concerning the actual destruction of physical property, one may speak with less certainty. It all depends upon the larger strategy. I have suggested the elimination of all life in such a city as Paris—or New York—as a possible result. That could be accomplished by such a gas as Lewisite. Now Lewisite whirled in a lethal cloud over Paris would not greatly injure property. When at length the poison was dissipated, the Opéra would still be there and the Louvre and the great railway terminals and the factories—a little corroded perhaps, but still usable after you cleaned out the corpses and tidied up a bit. So perhaps a better way of breaking up the “resistance of the rear” would be to exterminate not the human Paris but the physical Paris. That could be done in one gigantic conflagration started by inextinguishable chemicals dropped from a few aircraft. The method is practicable even now, in the infancy of chemical warfare; and the military chemists of Europe are experimenting further along these lines. Such a campaign would of course not be confined to Paris; although Paris as a centre for the brains of war, as the most vital knot in the railway web and as a great factory city, is eminently important. It would be aimed also at Lyons and St. Etienne, great manufacturing cities, at Marseilles, Cherbourg, Havre and Bordeaux, the great
