To overcome this difficulty, the trees which it was necessary to remove were sawed almost through and wired up to others, which were untouched, in order to keep them standing to the last moment. In order to get their field of fire, it was necessary for the men of some batteries to cut and wire as many as a hundred trees. In this way everything was prepared for the opening of the bombardment save the actual felling of the trees, and not the keenest eye nor the finest camera among the Boche aviators could detect a change in the character of the forest. At dusk on the night of Wednesday, September 25th, the artillerymen cut the wires holding the trees with axes and pulled the monarchs of the forest crashing to the ground to left and right of the path thus opened up, leaving the way clear for the artillery fire. A total of more than a thousand trees were felled in this way for the three regiments. CHAPTER XVII MILLION DOLLAR BARRAGE At eleven o'clock that night, September 25th, a signal gun barked far down the line. The gunners of every battery were at their posts, lanyards in hand, and on the instant they pulled. That has become known in the army as "the million dollar barrage," because enlisted men figured it must have cost at least that much. Whatever it cost, no man in that great army ever had heard the like. It ranged from the smaller field pieces up to great naval guns firing shells sixteen inches in diameter, with every variety and size of big gun in the American army in between. There had been talk in the war of a bombardment "reaching the intensity of drum fire." No drums the world ever has heard could have provided a name for that bombardment. It was overwhelming in the immensity of its sound, as well as in its effect. There were 3,000 guns on the whole front. Toward morning, the twelve ugly, snub-nosed weapons of the 103d Trench Mortar Battery, under Captain Ralph W. Knowles, of Philadelphia, added their heavy coughing to the monstrous serenade which rent the night. They were in position well up to the front, and their great bombs were designed to cut paths through the enemy barbed wire and other barriers so the infantry could go forward with as little trouble as possible. Zero hour for the infantry was 5.30 o'clock on that morning of September 26th. Watches of officers and non-commissioned officers had been carefully adjusted to the second the night before and when the moment arrived, the long lines went over the top without further notice. The former National Guard of Pennsylvania was but one division among a great many in that attack, which covered a front of fifty-four miles from the Meuse clear over into the Champagne and which linked up there with the rest of the whole flaming western front. The American army alone covered twenty miles of attacking front, and beyond them extended General Gourard's French army to the west.