About three o'clock in the morning sentries heard the whir of airplane motors, and fired their rifles. The sharpshooters of the regiment rushed to the edge of the woods with rifles and supplies of ammunition, and the anti-aircraft guns around Château-Thierry set up their baying. The 109th's marksmen tried a few shots, but the range was too great for effective shooting, and the flyers turned tail and disappeared in the face of the air barrage from the big guns before they got within good rifle range of our men. Next day the regiments remained in camp, and that night another battalion of the 109th stood guard on the bridges. This time the flyers apparently had crossed the river to the east or the west, for they came up from the south, directly over the bridges at Chierry, probably returning from an attempt to raid Paris. They rained bombs. There was no possible chance for the marksmen this time. Rather it was a question of keeping out of the way of the death-dealing missiles hurtling earthward. Again the anti-aircraft guns gave tongue, and after ten minutes or so of this explosive outburst the airplanes disappeared. Then the 109th learned something of the difficulties airmen experience in trying to hit a particular mark. Although the river had been churned to foam by the hail of bombs, only one bridge was hit and the damage to it was so slight as to be repaired easily. Early next morning, July 26th, the period of inaction came to an end. The regiments were ordered out on a route to the northeast, which would carry them somewhat east of Fere-en-Tardenois, in the middle of the Soissons-Rheims "pocket," which fell some days later. Orders were for the Pennsylvanians to press along that route with all speed until they effected contact with the retreating enemy, and to exert all possible pressure to harass him and push him as far and as rapidly as possible. Gradually, as the regiments moved forward, the sound of the firing became louder, and they realized they were overtaking the ebbing tide of Germans. Officers, having learned by bitter experience at the Marne the value of the British suggestion to do away in battle with marks distinguishing them as of commissioned rank, stripped their uniforms of insignia and camouflaged themselves to look like enlisted men. The officer casualties in those first few days of fighting could not be maintained without working irreparable harm to the organizations. Orders were issued to beware of every spot that might shelter a sniper or a machine gun. The regiments deployed into lines of skirmishers, greatly extending the front covered and reducing the casualties from shell fire. Patrols were out in advance, and every precaution was taken against surprise by parties of Germans that might have been left behind in the retreat.