From the moonlit aerodrome there rose into the quiet night a little two-seater B.E. 2C. machine, with a pilot and an observer as the crew. Soon this hummingbird of the darkness was winging its steady way across the German front lines, and met as opposition only the scattered and inaccurate firing of machine-gunners and rifle-men on the ground.

The observer closely compared his lamp-lit chart, and the pale map of the moonlit country below him. With unerring certainty the airmen moved across field and forest, farm and village, till they saw some distance ahead of them the gleam of a silver streak of water. As they drew nearer they saw the shining curves of a river, across which, at one point, lay a straight black line. It was their bridge.

At once the noise of the engine ceased and the machine began to sink gently on softly singing wires towards the ground. Bigger grew the woods, wider the thin white roads, deeper the soft and velvety shadows. Over the tops of some trees they floated. The rolling expanse of a field rose up to them. The machine quivered and jerked, and soon was rolling softly along the grass. Before it had stopped the observer had jumped out, and he hurriedly lifted a bulky package from his cockpit. He waved to the pilot. He heard the sudden roar of the engine, and the machine slipped faster and faster across the field and rose up towards the stars, leaving him alone on the ground in the midst of his enemies, many long miles from his own lines.

Quickly he ran to the edge of a wood, and he was soon creeping silently through the dim lattice-work of moonlight and rippling shadows. In a little while he heard the soft murmur of rapid waters, and he came to the edge of the river. He followed its course for a time, threading his way through the trees near the bank. When he could see the bridge some two hundred yards away he slipped into the river, and wading waist-high in the water, with his precious packet held well above the surface, he moved slowly and silently toward the moonlit arches of stone.

Above him he could now hear the hum of his machine, and he saw it sweep overhead quite low down. It turned rapidly and dived down straight towards the bridge, and he heard the pok, pok, pok of its machine-gun. With a great rush of sound it roared upwards again and banked steeply almost above him. Now he could hear the noise of an approaching train, and he saw the restless machine, whose pilot was deliberately distracting the attention of the sentries by his acrobatics and the noise of his engine, dive towards it. There was a sudden flash of light and a very loud detonation. The pilot had released one of his bombs. Then once more sounded the metallic hammering of his machine-gun.

Meanwhile the observer had reached the base of one of the stone piers which supported the bridge. The excited sentries had not noticed his presence, and now he was safely hidden in the gloom of the arch. With the water swirling round his waist he worked feverishly to remove one of the stones. At last it was loosened sufficiently to be withdrawn. In its place he put his precious packet, which was a charge of high explosive. This he secured firmly in position, and then, having set the fuse, he began to return, through the water, to his starting place. Another swift flash illuminated the leaves of the riverside bushes. It was followed by a second thundering explosion, as another bomb burst near the crowded troop train which still had not crossed the bridge.

In a few minutes he clambered up the bank and hurried through the magic beauty of the moonlit wood. He reached the edge of the field where he had landed, and stood waiting. He looked at the luminous face of his watch. The pilot was going to allow him fifteen minutes. Fourteen had passed. He knew his friend would not fail him whatever happened, so though he stood, soaking wet and alone, surrounded by the now angry enemy, he did not feel at all alarmed.

Overhead he heard the drone of the engine, which suddenly stopped, to be followed by the faint, scarcely-heard hiss of the wires as the machine began to glide downwards to the ground. Soon a shadowy shape moved swiftly across the ground and stopped. The observer ran over to it and climbed quickly into his seat. He shouted to the pilot of the success of his operation, and then with a roar and rush was borne upwards, and to his relief found himself flying swiftly once more through the friendly air.

Even as they turned to start on their long homeward journey a great sullen roar rose to them from below, and they saw that no more across the silver streak of the river lay a black line, for now it was obscured by a cloud of smoke, which slowly dissipated and revealed a great gap in the bridge, near which was the red glow of the locomotive that no longer could take forward its carriages loaded with troops destined for a now impossible railhead.

That happened in the early days of the war. Swiftly developed the powerful arm of the air. Great were the changes in thought. Mighty the new weapons of destruction....