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.