From Les Eparges around the nose of the salient at St. Mihiel to the Moselle River the line was, roughly, forty miles long and situated on commanding ground greatly strengthened by artificial defenses. Our 1st Corps (82d, 90th, 5th, and 2d Divisions), under command of Major Gen. Hunter Liggett, resting its right on Pont-à-Mousson, with its left joining our 3d Corps (the 89th, 42d, and 1st Divisions), under Major Gen. Joseph T. Dickman, in line to Xivray, was to swing toward Vigneulles on the pivot of the Moselle River for the initial assault. From Xivray to Mouilly the 2d Colonial French Corps was in line in the centre, and our 5th Corps, under command of Major Gen. George H. Cameron, with our 26th Division and a French division at the western base of the salient, was to attack three difficult hills--Les Eparges, Combres, and Amaranthe. Our 1st Corps had in reserve the 78th Division, our 4th Corps the 3d Division, and our First Army the 35th and 91st Divisions, with the 80th and 33d available. It should be understood that our corps organizations are very elastic, and that we have at no time had permanent assignments of divisions to corps. After four hours' artillery preparation, the seven American divisions in the front line advanced at 5 A. M. on Sept. 12, assisted by a limited number of tanks, manned partly by Americans and partly by French. These divisions, accompanied by groups of wire cutters and others armed with bangalore torpedoes, went through the successive bands of barbed wire that protected the enemy's front-line and support trenches in irresistible waves on schedule time, breaking down all defense of an enemy demoralized by the great volume of our artillery fire and our sudden approach out of the fog. Our 1st Corps advanced to Thiaucourt, while our 4th Corps curved back to the southwest through Nonsard. The 2d Colonial French Corps made the slight advance required of it on very difficult ground, and the 5th Corps took its three ridges and repulsed a counterattack. A rapid march brought reserve regiments of a division of the 5th Corps into Vigneulles and beyond Fresnes-en-Woevre. At the cost of only 7,000 casualties, mostly light, we had taken 16,000 prisoners and 443 guns, a great quantity of material, released the inhabitants of many villages from enemy domination, and established our lines in a position to threaten Metz. This signal success of the American First Army in its first offensive was of prime importance. The Allies found they had a formidable army to aid them, and the enemy learned finally that he had one to reckon with. MEUSE-ARGONNE OFFENSIVE, FIRST PHASE