With a grunt the tanks heaved their prodigious menace on. The Germans did not wait for their coming. They scattered and fled in all directions. They were willing enough to invent new distortions of war, such as poison gas and liquid fire, but, in childish unreason, they became furious when any new device was directed against them. Yet still the brutes of steel crawled onward, growling, as their sponsons spit flame. For six months the trenches on either side had remained unbroken. In sixty minutes, two tanks, backed up by the French infantry, had driven the Germans back, captured a thousand prisoners, taken several score machine guns and frightened an entire German army corps into wild-eyed and headlong panic. Its morale was broken and in spite of their officers' commands, they dared not return to the charge. The French captured and consolidated the trenches, which were underground forts of surprising strength. One of the communication trenches was more than a hundred yards long, completely lined with timber and carried so deep underground as to be safe from anything but mining. There were dug-outs entered through a steel door, two stories in depth, with spacious rooms closely boarded. In one such dug-out, there were evidences that one of the officers had been living in comfort, with his wife and child. Another was fitted with a hydraulic mechanism for sending up excavated earth to be used in sand bags. Some of the larger dug-outs could easily hold a platoon of men in complete security. Several tunnels led to sniper stations, like a manhole to a sewer, reaching the surface at high points. These were well timbered, with iron ladders. The trenches were lined with concrete, warm and dry. The manual labor was astounding. Contrasted with the French trenches, roughly built and damp, the German advantages all winter had been enormous. The distant German batteries, changing their range to the location of their former trenches, commenced a heavy bombardment, but the consolidation had been rapidly effected, the French artillery had advanced without delay, engineering companies had put up new wire entanglements, and though, for a week without cessation, the Germans charged again and again, they were pushed back with heavy losses. And when, ten days later, an attack was made in force, Mesdames Tank waddled to the front again and the Germans fled in dismay. Little by little the German line was pushed back, little by little the soil of France was rewon. But, for Horace, the end was not yet. One bright spring morning, while busy at his switchboard in the little shelter which had been constructed for the telephone, the boy heard a thin, high whistle and a small shell crashed through the roof. It struck the floor and exploded, thin splinters flying in every direction. Dazed with surprise that he had not been blown up sky high, Horace realized that this could not be a high explosive bomb. It must be a gas shell.