The preparation for a complicated operation against the formidable defenses in front of us included the assembling of divisions and of corps and army artillery, transport, aircraft, tanks, ambulances, the location of hospitals, and the molding together of all the elements of a great modern army with its own railheads, supplied directly by our own Service of Supply. The concentration for this operation, which was to be a surprise, involved the movement, mostly at night, of approximately 600,000 troops, and required for its success the most careful attention to every detail.
The French were generous in giving us assistance in corps and army artillery and we were confident from the start of our superiority over the enemy in guns of all calibres. Our heavy guns were able to reach Metz and to interfere seriously with German rail movements. The French Independent Air Force was placed under my command, which, together with the British bombing squadrons and our air forces, gave us the largest assembly of aviators that had ever been engaged in one operation on the western front.
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.