Then, like a cat, he dropped to the ground again, and pressed an ear to it. For his ears had caught a tiny betraying hum.
A hum! There was a machine of some type near him. He listened intently. The hum came from the ground on which he lay. There had to be a trap-door.
Lance's fingers scrabbled around, and presently found what they looked for.
He seized the ring which enabled one to pull the trap-door back, and was just about to pull when he heard, from below, a voice speaking in Russian. It was, then, the spy!
Lance grasped the ring anew, and, exerting all his strength, hauled the trap-door back.
A narrow passageway was revealed, lit by a lamp. The hum burst with doubled force on his ears. He plunged down, fists clenched, and half tumbled into a tiny room gouged from the soil.
At one end was a mass of machinery, and a microphone hung suspended before it. And speaking into the microphone was the heavy-set form of a man in American uniform, his back to Lance. As the latter charged down, he rose with an alarmed shout, and wheeled around.
"My God!" breathed Lance.
It was Ranth, Colonel Douglas' orderly!