An early attack by the Germans was made behind a dense fog after daybreak, through which came a violent artillery barrage as a forerunner. The fog was of a density that blotted out everything but the nearest enemy positions. Through it enemy projectiles exploded on three sides of an American listening post just outside the wire, within forty-five feet of an enemy listening post. In a few minutes hundreds of high-explosive shells had dropped round the post and the surrounding ground, cutting off the men there. American artillery replied; but all traces of German dead and wounded were removed by the time the Americans had emerged from their dugouts after their barrage was raised. The Germans followed their sortie against the listening post by a heavy bombardment of the American lines a few days later. American guns responded, shell for shell, wrecking several of the enemy's dugouts, and badly damaging some of his first-line positions. They were caved in by the American 75's, and the Germans spent several days in repairing them and patching up gaps in the barbed wire before the wrecked trenches could be reoccupied. A number of the men who were wounded slightly by shell splinters were treated in the lines with their first-aid packets and insisted on remaining at their posts until the fight was finished. The enemy's next artillery exercise was a concentrated fire on one of the American positions with the object of obliterating it. Americans guns at once punished the German batteries with a retaliatory fire of double force, and then swept the enemy lines with a vicious barrage. Whereupon the German guns ceased firing. The enemy presently resorted to the use of gas to harass the American positions. Aimed at a wood, a rain of shells, largely composed of gas and high explosives, came from the German minenwerfers. They burst in the air, the high explosives detonating when they came in contact with the earth, and broke into fragments among a number of men before they could adjust their masks. Other troops were overcome by the fumes while asleep in their dugouts. The fumes lingered in the gassed area long after the shells had exploded, filling shell holes and other depressions, and incapacitating men who ventured to work in the vicinity. But the American guns exacted swift retribution. They leveled a heavy fire on the German minenwerfers, and in half an hour had razed the position. Timbers were thrown high in the air, and explosions, probably of enemy ammunition, testified to American marksmanship. The ground about the German batteries was churned upside down, and there was no doubt of the fate of any German soldiers who were on the spot.