The engineers had no time to spare for observing blazing balloons. Their labors in the old trench system, in contrast to the florid drama of the air, were a reminder of how completely earth-tied the army was, and how small a part of its effort was above the earth, even in the days when communiqués paid much attention to aces. For a mile or more every road in the immediate rear of the old French trenches had been in disuse for four years while it was being torn by shell-bursts. For the distance across No Man's Land, it had become part of the sea of shell-craters. On the German side of No Man's Land were more trench chasms, and another stretch which had been blasted in the same fashion as the French side. Shoveling would fill many of the holes; but shoveling required labor when we were short of labor, and time when every minute was precious. It was increasingly evident every minute, too, that trucks that carry three tons, and six-inch mortars, and heavy caissons were not meant to pass over any piece of mended road that had its bottom two or three feet below the surface. They insisted upon finding the bottom and remaining there until pulled out by other traction than their own. The division engineers were supposed to keep on the heels of the infantry, which they did with a gallantry which made amends for the inadequacy of their numbers and material. Their efficacy was dependent upon these two features and upon the prevision of the division command in mastering the problem beforehand. There were critics who said that some division staffs evidently expected their artillery and rolling kitchens to take wing; but the division staffs produced by way of answer the unfailing list of written orders on the subject, which could not be carried out. If the infantry were repulsed or checked, the engineers might share some of the fighting, as they had on more than one occasion. There seemed to be a universal apprehension, the engineers said, that an engineer might have a chance to sleep or rest, which would obviously ruin his morale. If, after the infantry had passed on, the enemy concentrated the fire of a battery on the road-builders, they were not supposed to be diverted from their labor, but to be prompt in filling new shell-craters.