was to these loyal and amiable beings that ITA's engineers turned for workers who could endure the stifling heat of the underground workings.

The tent-flap was thrust aside, and a hawk-nosed Scot came sleepily in, to be enthusiastically greeted by Jim.

"Hello, you old Caledonian. 'Bout time you showed up."

The newcomer fixed the speaker with a dour gaze. "An' why should I commence my tour o' dooty befair the time?"

"Because your chief, Mr. Darl Thomas, decided that he's a filliloo bird or somethin', flew to his little nest up top, an' forgot to come down again."

"Is this ain o' your jests, James Holcomb? I eenquire mairly that I may ken when to laugh."

"It's no joke, Mac. Last I see o' him he's skippin' around the roof like he has a buzzin' propeller stuck to his shoulder blades. He lights on th' air-lock platform, pops inside, an' goes dead for all I know."

From his bony legs to his scrawny neck the Scotchman's angular body, as nearly nude as that of the others, radiated the doubt that was expressed in every seam and wrinkle of his hatchet face.

"That's straight, Angus, may I kiss a pink-eared vanta if it ain't. Here's what happened." The bantering grin disappeared from Jim's countenance as he detailed the events that had preceded Darl's vanishing. "That was two hours ago," he concluded, "and I've been getting pretty uneasy about him."

"Why did na ye call me, so that ain o' us micht eenvestigate?"

"Hell. Darl wasn't born yesterday, he can take care of himself. Besides, your last shift was pretty strenuous, an' I thought I'd let you sleep. No tellin' what might happen next; this forsaken place has been givin' me the jim-jams lately."

"Your conseederation is touching, but—" A scratching at the door, accompanied by a high squeak, interrupted him.

To Jim's shouted "Come in," there entered a Venusian, whose red rosette fastened to the green scales of his skin marked him an overseer. In the thread-like fingers of his hand he held a time-sheet, but the nervous pulsing of his gill-membranes caused Holcomb to exclaim anxiously: "What's wrong, Ran-los? No accident, I hope?"

The shrill combination of squeaks and twitterings that came from the man-reptile's toothless mouth meant nothing to the Scot, but Jim's last service had been on Venus and he had gained a working knowledge of the language. Finally the interchange was ended, and Ran-los bowed himself out. Jim turned to his companion.

"There's some more queer stuff for you, Angie. Just before shift-change, Ran-los heard odd sounds from the other side of the barrier at the end of gallery M-39. Says they seemed like signals o' some kind. He's a wise old bird and if he's worried about something it's damn well worth lookin' into. I don't know whether to find out first what's happened to Darl, or—"

Again there was an interruption; this time from the usually silent radio-communication set in the far corner. Jim leaped to the instrument and snapped on the head-set. Angus leaned over him, watching his intent face.

Faintly, as from an immense distance, came the thin whistle of space-radio. "S-W-A ... S-W-A ... S-W-A...." The general attention signal for all Earth's far-flung outposts from Jupiter to Mercury! The signal was coming from "M-I-T-A," the Earth company's home station on the Moon, outside the Heaviside layer. "S-W-A ... S-W-A ... M-I-T-A ... M-I-T-A." Again the signal rose and fell.

Jim reached for the sending key and pounded out his acknowledgement: "K; M-E-R ... K; M-E-R ... K; M-E-R." He listened again, heard Venus answer, and Jupiter. Across five hundred million miles of space ITA men were responding to the roll-call of Earth. A reminiscent smile crossed Jim's face as he recognized the stuttering fist of Rade Perrin, on Eros. Rade always sent as if he were afraid the instrument would snap at his fingers.

M-I-T-A was signalling again, and now came the message: "S-W-A. All trading posts, mines and colonies are warned to prepare for possible attack. The Earth Government has just announced the receipt of an ultimatum from—" A raucous howl cut across the message and drowned it out. The siren blast howled on and on, mocking Jim's straining ears. "Well I'll be—Interference! Deliberate blanketing! The rats! The—" He blazed into a torrent of profanity whose imaginativeness was matched only by its virulence.

Mac was clutching his shoulder, stirred for once out of his vaunted "deegnity." "What is it, mon, what is it?"

"War, you bloody Scotchman, war! That's what it is!"

"War! Foosh, man, 'tis eempossible!"

"The hell it's impossible! Damn, and Darl not here! Take over, Mac; I've got to go up an' get him!"

In the meantime Thomas' helpless journey had come to an end. After an interminable descent in what to him had been pitch darkness, the giant who was carrying him halted. Darl had heard the whistling inrush of air into some lock, then the clanging of a door. He felt himself hurled to the ground. Fumbling hands tugged at him, drew off his space suit.

The dim light of the cavern, as the helmet was dragged from his head, hurt Darl's eyes. Salt sweat stung them. It was hot, hotter than the Dome, hot as it was in the surta mine, where only the nerveless Venusians could work for any length of time.

Darl struggled to focus his eyes on a blurred blue form that towered above him. He felt sharp claws scratch at him and realized that cords were being passed around his limp body. They cut tightly into his legs and his arms. Then he was staring at a tube in the hand of his captor. Its end glowed with a brilliant purple light, and he felt a flood of reawakened energy warm him. His head jerked up, he strained against the taut, strong fibers binding him. The paralysis was gone, but he was still helpless.

A husky, rumbling voice broke the silence. "I wouldn't struggle, Earthman, if I were you. Even should you get free I still have my ray-tube. And my little friends would ask nothing better than your body to play with."

Darl writhed to a sitting posture. Now he could see his mysterious abductor clearly. This eight-foot, blue-feathered individual, with curved beak and beady eyes glittering from his naked, repulsively wrinkled head, was a Martian! Despite the human shape of his body, despite his jointed limbs and thumbed hands, this denizen of the red planet resembled a vulture far more than he did any other Earth creature.

The Earthman's pride of race came to his rescue. "What's the game?" he growled. "Looking for trouble?" There was nothing in Darl's voice to show the fear that chilled him. Behind the Martian he could see vaguely a group of little yellow Mercurians.

"I'll ask all the questions here. And you'll answer them, too, if you're wise. Even your dull mind should comprehend that you are in my power."

Darl decided to proceed more cautiously. "What do you want from me?" he asked.

"I want," the Martian answered, "the recognition signal of Earth's space-ships."

"What!" The ejaculation burst from Darl's throat. This alien wanted the secret code, the watch-word that distinguished Earth's space ships, that gained for them free admittance to ITA's armed posts on the outer planets! This could mean only one thing, that the long rivalry, the ancient dispute between Earth and Mars was about to flare into open war. Any friendly visit from a foreign flier would be heralded by word from M-I-T-A. Thomas' face became a stony mask, covering the tumult of his mind.

"You understood. I want the Earth recognition signal at once—and after that, the surrender of the Dome." The very calmness of the husky tones was a threat.

"Never!"

"I warn you, Darl Thomas. It would be the better part of wisdom for you to yield willingly what I ask. You will give in eventually, and the means