Whitey made a hasty and very bad landing. His craft bounced and careened but kept upright. It halted near the cliff. The scared passengers piled out. 6 sweating men and one defiant-but-helpless blonde girl.
Catching sight of Monk’s secretary, Doc popped from the gulch.
But a rain of bullets fired from the cliff ruin drove him back.
Buttons Zortell ran up the rope ladder to safety. Whitey followed, then the others.
Lea Aster refused to climb. So they tied her to the lower end of the ladder and pulled her up after the last man had ascended.
Flying the gyro, Renny now dropped down to take Doc aboard. This maneuver was covered by machine-gun fire from the speed plane.
“I believe we have the entire gang cornered,” Doc told Renny as the gyro lifted out of gunshot of the ruin.
“Their big chief, too?” Renny demanded.
“I believe so. He arrived shortly before the plane got in from New York. And every man back of them is now in that cliff dwelling.”
“What did their leader look like?”
“Search me!” Doc retorted, then explained that he had been able to distinguish nothing because of the gabardine coat.
“Well, their goose is cooked anyhow!” Renny boomed. “They’ve trapped themselves. They can’t escape down the face of that cliff. And not even a fly could climb upward!”
XIII — Hot Rock
Doc now issued low orders.
Complying with them, Renny maneuvered the windmilling gyro in close to the cliff face. Pushing the control wheel forward gently, he lowered the strange craft.
From within the ruin, a man sought to shoot upward. But after releasing a single bullet, he was driven to cover by a blast of lead from the monster speed plane.
The latter craft was cruising back-and-forth along the cliff face. It was no mean feat of piloting! Monk was at the controls. All of Doc’s 5 aides were expert flyers.
The flare burning in the tin tub was extinguished. The darkness which ensued was only momentary. The speed plane dropped a ‘chute flare to take its place.
There was no more shooting from within the ruins. Nor did the villains show themselves although they must have known the gyro was nearing the rectangular openings which gave access to their stronghold. This seemed a bit strange.
When within a few yards of the first aperture, Doc flung a glass ball which was nearly as large as a grapefruit. This passed into the ancient cliff dwelling structure and burst.
It held the instantaneously effective, quick-dissipating anesthetic gas — the exact composition of which was known to no one but Doc.
The silk cord and grapple which had served him earlier in the night were now brought into use. From the fairly steady cockpit of the gyro, Doc tossed the grapple repeatedly until it hung on the edge of an opening in the ruin. Then he dropped the cord down the cliff face.
Renny promptly landed the gyro, permitting Doc to alight and climb the cord.
To a man of ordinary strength, mounting the slender line of silk might have presented an impossible task. The small size made gripping difficult.
But Doc’s hands possessed amazing strength thanks to an intensive system of exercises which he took each day of his life.
He climbed swiftly. Not once did the cord slip through his powerful grasp!
“Hear anything?” Renny called anxiously from below.
“No,” Doc replied after listening.
Renny’s sigh of relief came up distinctly. “I guess the gas got ‘em!”
Some 40 feet below his objective, Doc suddenly halted. His sensitive nostrils moved slightly as he sampled the air.
“What is it?” Renny asked.
“An odor… as though something were burning!” Doc explained.
“That’s probably from the flares.”
Doc said nothing more. But this scent that he had detected did not come from the flares. Of that, he was convinced. The question of just what it was had him baffled. It had a tang new to his experience.
He slid back down and joined Renny.
“It might be some type of poison gas,” he answered Renny’s look of surprise. “The odor is very strange!”
Monk brought the speed plane down in a graceful landing. The big craft taxied close and its 4 passengers alighted.
The cabin still held several cases and boxes. From one of these, Doc dug his chemical-reaction device for ascertaining the presence of poison gas. He also got another object — a large glass bottle which could be sealed absolutely tight.
With these slung on his back, he mounted the silk cord. No stir, no sound of life came from the ruin.
There was nothing poisonous about the strange odor, his apparatus told him.
He promptly entered the cliff dwelling.
To his surprise, there was no sign of tubby Jud or the other men who had fallen victim to the gas-in-the-coatsleeve trick.
Doc tossed the rope ladder down to his men. They joined him with the exception of Long Tom and Ham who remained on watch. There was always a chance more of the villains would arrive by plane.
The strange odor became stronger as they stepped into an inner room of the ancient structure. Doc played his flash beam about. It revealed a circular hole in the floor. The end of a pole projected from this. Notches had been cut into the pole, making it a ladder of sorts.
Leaning over the hole, Doc found the weird smell much stronger. And there now seemed to be heat!
Renny, Monk, and Johnny had scattered to other rooms. They came back, puzzled.
“There’s no sign of the gang!” they reported.
“They must’ve gone down that hole,” Monk grunted.
Doc dropped anesthetic down the gaping aperture. He and his men gave it the necessary minute to become ineffective… then descended.
They found themselves in one of several chambers chipped out of solid stone. These were floored with the rubble of ages.
Spying another floor opening and making sure the odor — and intense heat — was coming from it, Doc descended. The others followed.
“Holy cow!” Renny ejaculated. “Somethin’ must be awful hot in there ahead of us!”
“Monk!” Doc called. He had lost sight of the hairy chemist.
“I’m just lookin’ in here,” Monk informed him from another room. “These chambers seem to have been a granary. I see a lot of corn cobs around.”
“Did you ever smell anything like this odor?” Doc questioned.
Monk sniffed noisily. “Bless me, no!”
“You sure? I thought perhaps you had caught such a scent while mixing chemicals.”
“Never did. And say! where’d everybody go to? And where’s that heat comin’ from?”
His flash beam playing ahead, Doc ducked through a low door. The heat was more intense. It increased as he advanced.
A strange reddish panel became visible ahead. This proved to be another door with a great mass beyond it glowing at a red heat!
Doc stopped and stared in wonder. Monk and Renny came up behind him.
“That looks like red-hot lava!” Monk muttered in awe.
They sidled forward gingerly.
The heat was terrific! It dried the moisture in their eyes and set perspiration trickling on their skin.
Yet the source of the terrific temperature was fully 40 feet distant at the end of a long chamber which was half room and half passage.
The whole end of the subterranean room glowed a cherry color.
In one corner, the solid stone seemed to have melted! Not unlike red cotton, the molten rock had oozed outward over an area of several square feet, pouring out into a shape that resembled a human skull!
With a quick gesture, Doc uncorked the glass flask he had brought. He fanned it about briskly until it contained a quantity of the air within the stone cubicle. Then he corked it.