another pair which separated at the second joint into limber tentacles, each of which ended in a cluster of hair-fine appendages. The globes were joined by a wasp’s slenderness of waist. As far as Dane could see, and he couldn’t bring himself to the close examination which absorbed Tau, there were no features at all—no eyes, ears, or mouth.
But the oddest sight of all were the globes which formed the body. They were a greyish-white, but semi- transparent. And through the surface one could sight reddish structural supports which must have served the creature as bones, as well as organs Dane had no wish to explore.
“Great space!” Ali exploded. “You can look right through them!”
He was exaggerating—but not so much. The Limbians—if this were a Limbian—were far more tenuous than any creature the Terrans had found before. And Dane was sure that the record film would show that it was a thing such as this which had passed the contact point in the other valley.
Ali stepped around the body to examine the scars left by the blast which had driven the creature into the crevice. He touched a finger gingerly to a blackened smear on the rock and then held it close to his nose.
“Blaster right enough.”
“Do you think Rich—?”
Ali gazed down the valley. Like all the others they had yet sighted it ran from the towering mountains to the blasted plain, and they could not be too far from the ruins where the archaeologists had gone to earth.
“But—why?” Dane asked a second question before his first had been answered.
Had the globe things attacked Rich and his men? Somehow Dane could not accept that. To his mind the limp body Tau was working over was pitifully defenceless. It held not the slightest hint of menace.
“That’s the big question.” Ali tramped on, past the hollow where lay those other dreadfully contorted bodies, down to the edge of the stream, which this valley, as did all the cultivated ones, cradled in its centre, the fields strung out along it.
Plain to read here was the mark of the invader. No feet had left that pair of wide ruts crushed deep into the soft ground of the fields. Dane stopped short.
“Crawler! But our crawlers—”
“Are just where they should be, parked under the Queen or in their storage compartments,” Ali finished for him. “And since Rich couldn’t have brought one here in a kit bag, we must believe that Limbo is not as barren of life as Survey certified it to be.” He stood at the edge of the stream and then squatted to study a patch of drying mud. “Track’s odd though—”
Although his opinion had not been asked, Dane joined the Engineer-apprentice. The tread mark had left a pattern, clear as print, for about four inches. He was familiar with the operation of crawlers as they pertained to his own duties. He could even, if the need arose, make minor repairs on one. But he couldn’t have identified any difference in vehicles from their tread patterns. There he was willing to accept Ali’s superior learning.
Kamil’s next move was a complete mystery to Dane. Still on his knees he began measuring the distance between the two furrows, using a small rule from his belt tool kit for a gauge. At last Dane dared to ask a question:
“What’s wrong?”
For a moment he thought that Ali wasn’t going to answer.
Then the other sat back on his heels, wiped dust from the rule, and looked up.
“A standard crawler’s a four-two-eight,” he stated didactically. “A scooter is a three-seven-eight. A flamer’s carriage runs five-seven-twelve.”
The actual figures meant very little to Dane, but he knew their significance. Within the Federation machinery was now completely standardized. It had to be so that repairs from one world to the next would be simplified. Ali had recited the measurements of the three types of ground vehicles in common use on the majority of Federation planets. Though, by rights, a flamer was a war machine, used only by the military or Patrol forces, except on pioneer worlds where its wide heat beam could be turned against rank forest or jungle growth.
“And this isn’t any of those,” Dane guessed.
“Right. It’s three-two-four—but it’s heavy, too. Or else it was transporting close to an over-load. You don’t get ruts like these from a scooter or crawler travelling light.” He was an engineer, he should know, Dane conceded.
“Then what was it?”
Ali shrugged. “Something not standard—low, narrow, or it couldn’t snake through here, and able to carry a good load. But nothing on our books is like it.”
It was Dane’s turn to study the cliffs about them. “Only one way it could go—up—or down—”
Ali got to bis feet, “I’ll go down,” he glanced over at the busy Tau engrossed in his grisly task, “nobody’s going to drag him away from there until he learns all he can.” He shuddered, perhaps in exaggeration, perhaps in earnest. “I have a feeling that it isn’t wise to stay here too long. Any scout will have to be a quick one—”
Dane turned up stream. “I’ll go up,” he said firmly, it was not Ali’s place to give orders, they were equal in rank. He started off, walking between the tracks without looking back.
He was concentrating so on his determination to prove that he could think properly for himself that he made a fatal slip, inexcusable in any Trade explorer. Though he continued to wear his helmet, along with all the other field equipment, he totally forgot to set his personal com-unit on alert, and so went blindly off into the unknown with no contact with either of the others.
But at the moment he was far more intent on those tracks which lured him on, up a gradually narrowing valley towards the mountain walls. The climbing sun stuck across his path, but there were pools of purple shadow where the cliffs walled off its rays.
The trail left by the crawler ran as straight as the general contour of the ground allowed. Two of the lacy winged flying things they had glimpsed in the other valley skimmed close to the surface of the stream and then took off high into the chill air.
Now the greenery was sparser. He had not passed a field for some time. And underfoot the surface of the valley was inclining up in a gentle slope. The walls curved, so that Dane walked more warily, having no desire to round a projection and meet a blaster user face to face.
He was certain in his own mind that Dr. Rich had something to do with this. But where did this crawler come from? Had the Doctor been on Limbo before? Or had he broken into some cache of Survey supplies? But there was Ali’s certainty that the vehicle was not orthodox.
The trail ended abruptly and in such a manner as to stop Dane short, staring in unbelief. For those ruts led straight to a solid, blank wall of rock, vanishing beneath it as if the machine which had made them had been driven straight through!
There is always, Dane hastily reminded himself, some logical explanation for the impossible. And not Video ones about “force walls” and such either. If those tracks went into the rock, it was an illusion—or an opening—and it was up to him to discover which.
His boots crunched on sand and gravel until he was in touching distance of the barrier. It was then that he became aware of something else, a vibration. It was very silent there in the cramped pocket which was the end of the valley, no wind blew, no leaves rustled. And yet there was something unquiet in the air, a stirring just at the far edge of his sensitiveness to sound and movement.
On impulse he set the palms of his hands against the stone of the cliff. And he felt it instantly, running up his arms into his body until his flesh and bones were only a recorder for that monstrous beat-beat-beat—relayed to him through the stuff of Limbo itself. Yet, when he passed his fingers searchingly over the rough stone, studied each inch of it intently, he could see no break in its surface, no sign of a door, no reason for that heavy thump, thump which shook his nerves. The vibration was unpleasant, almost menacing. He snatched his hands away, suddenly afraid of being trapped in that dull rhythm. But now he was sure that Limbo was not what it seemed— a lifeless, dead world.
For the first time he remembered that he should have maintained contact with the others, and hurriedly turned the key on his com-unit. Instantly Tau’s voice rang thinly in his ears.
“Calling Ali—calling Thorson—come in—come in!” There was an urgency in the Medic’s voice which brought Dane away from the wall, set him on the back trail even as he replied:
“Thorson here. Am at end of valley. Wish to report—”
But the other cut into that impatiently. “Return to flitter! Ali, Thorson, return to flitter!”
