50 in 50

"A hovercraft.” Bron said. "They aren't seen very much these days — but they do have their uses. They can move over any kind of open country or water, and they don't leave tracks. But they can't go over or through forest."

"I've never heard of anything like that."

"You wouldn't have. Since beamed power and energy cells came into general use, better means of transportation have been developed. But at one time they used to build hovercraft as large as houses. They are sort of a cross between ground and air transport. They float in the air, but depend upon the ground for support, since they float on a column of air being blown down out of the bottom."

"You knew this thing was coming — that's why you had us hide in the woods?"

"I suspected this. And for very good reasons, I suspected them." He pointed inside the wrecked hovercraft, and Haydin recoiled in shock.

"I tend to forget — I guess everyone does," the Governor said. "I've only seen pictures of aliens, so they are not very real to me. But these creatures. Blood, green blood. And it looks as if they're all dead. Gray skin, pipestem limbs, just from the pictures I've seen, is it possible that they could be…"

"Sulbani. You're right. One of the three intelligent races of aliens we've met in our expansion through the galaxy — and the only ones who possessed an interstellar drive before we appeared on the scene. They already had their own little corner of the galaxy staked out and did not at all appreciate our arrival. We have been staying away from them and trying to convince them that we have no territorial ambitions on their planets. But some people are hard to convince. Some aliens even more so. The Sulbani are the worst. Suspicion is in their blood.

"All of the evidence seemed to point to their presence here on Trowbri, but I couldn't be absolutely sure until I came face-to-face with them. The use of high-frequency weapons is typical of them. You know that if you raise the pitch of sound, higher and higher, it becomes inaudible to human ears — though animals can still hear it. Raise it higher still and the animals can't hear it — but they feel it just as well as we can. Ultrasonics can do some strange things."

He kicked at one of the bent discs, not unlike a microwave aerial. "That was the first clue. They have ultrasonic projectors in the forest, broadcasting on a wavelength that is inaudible, but causes a feeling of tension and uneasiness in most animals. That was the ghostly aura that kept people away from this plateau most of the time." He whistled a signal for the herd to assemble. "Animals, as well as men, will move away from the source, and they used it to chase some of the nastier wildlife towards us. When it didn't work and we came back, they sent in the more powerful stuff. Look at your shoes — and at this lantern."

Haydin gasped. The eyelets had vanished from his boots, and ragged pieces of lace hung from the torn openings. The lantern, like the metal equipment of the lost expedition, was squeezed and bent out of shape.

"Magnostriction," Bron said. "They were projecting a contracting and expanding magnetic field of an incredible number of gauss. The technique is used in factories for shaping metal, and it works just as well in the field. That, and these ultrasonic projectors to finish the job. Even a normal scan radar will give you a burn if you stand too close to it, and some ultrasonic wavelengths can turn water to vapor and explode organic material. That's what they did to your people who camped here. Swept in suddenly and caught them in the tents surrounded by their own equipment, which exploded and crunched and helped to wipe them out. Now let's get going."

"I don't understand what this means. I—"

"Later. We have to catch the one that got away."

On the side of the clearing where the machine had disappeared, they found a ragged length of black plastic. "Part of the skirt from the hovercraft.” Bron said. "Confines the air and gives more lift. We'll follow them with this." He held out the fabric to Queeny and Jasmine and the other pigs that pressed up. "As you know, dogs track by odor that hangs in the air, and pigs have just as good noses — or better. In fact, hunting pigs were used in England for years, and pigs are also trained to smell out truffles. There they go!"

Grunting and squealing, the leaders started away into the darkness. The two men stumbled after them, the rest of the pigs following. After a few yards, Haydin had to stop and bind his shoes together with strips from his handkerchief before he could go on. He held Bron's belt, and Bron had his fingers hooked into the thick bristles that formed a crest on Curly's spine, and in this way they pushed through the forest. The hovercraft had to go through open country, or their nightmare run would have been impossible.

When a darker mass of mountains loomed ahead, Bron whistled the herd to him. "Stay," he ordered. "Stay with Queeny. Curly, Moe, and Jasmine — with me."