Upon some dark height full three miles away toward the Junction, and evidently some distance beyond the stream, a bright light, as of a lantern with brilliant reflector at its back, was shining steadily. "There was another a mile to the north of us as we crossed the last open common," said Stark. "Why, look! There it is again, yet it was dark just now."
And then, suddenly as that northern light appeared, it was extinguished or hidden. Then, before any one could speak, again it flamed. Again it disappeared, and the explanation occurred to all three at the same instant. "Signalling, of course," muttered Upton. "Now get two companies into line, facing west; then we'll leave our horses with them and creep out toward the bridge."
Another moment, and while Flint was noiselessly leading the foremost two into line, the major and the staff-officer had dismounted, handed their reins to silent Snipe, and out they went, crouching low, into the westward darkness, while every man breathed hard and listened. Then the southern light began to flash and disappear alternately. "We are far out to the west of Centreville," murmured Flint. "Those windows are hidden from that point. They doubtless think no one can see them here."
Five minutes, and still no sound came from their venturesome scouts. They had had time to go all the way across if need be. "What d'you s'pose they signal for?" whispered a young soldier in the leading set, whereupon the sergeant turned and muttered, "Hush!" and men began to realize that it was a time to listen—not to talk.
All of a sudden, low, clear, and distinct, a whistle was sounded not four hundred yards away. The first thought to strike every man was, the major! but the major had gone straight to the west; this sound came from across the wide field well to the northward of the supposed position of the bridge. Before there was time to comment the answer was given straight out ahead, soft, yet just as distinct. Then all three horses left with Snipe pricked up their ears and whirled toward the northwest, for from that quarter came the sound of hoof-beats, the low thud and rumble of horses moving at lively lope. Swift, invisible, they swooped down from the northward across the front. Then came sudden check, then silence, then the next minute the hollow sound of iron-shod hoofs upon resounding boards. First one horse, at a walk, then two, three, half a dozen together, and then silence again.
Two minutes later, back from the front, running, came the major. "Forward, just as you are!" he muttered to Flint. "The bridge is safe," and, swinging into saddle and bidding Snipe come on with the lieutenant's horse, he sped swiftly away across the field. At its western limit, at the edge of a deep, black trench that stretched away southward toward Bull Run, they found the staff-officer, standing at the old wooden bridge.
"They've left it intact," murmured Upton, gleefully, "and they've been scouting around our right flank for indication of any attack from this direction, and have missed us entirely. Now let 'em come back and get it if they can!"
In ten minutes three of Stark's strong companies had stacked arms among the timber to the west of the clumsy yet precious structure. The fourth was chosen for guard and picket duty, and, under the guidance of the energetic young staff-officer, every approach was covered. Wary sentries were stationed five hundred yards away, up and down the unsightly trough and well out toward the winding run, with supports and small reserves intervening between them and the main body. Even the open field to the east was guarded, for Major Stark meant that no enemy should come upon him unawares. Finally, deep in the shelter of the grove, they struck a light and consulted their watches. "Just half-past nine," said Upton, "and at midnight the move begins. Now I'll ride back and report. What splendid luck thus far!"
"You have no orderly, lieutenant," said Major Stark. "Let Lawton ride back with you until you reach our lines. I'd be better satisfied."
"There is no need, thank you, major. There is no likelihood of my meeting rebel patrols between this and our pickets. Those fellows are back across Bull Run by this time and riding away to tell Beauregard the Yanks have no idea of reaching round him this way."