Arriving at his worked-out New York State farm, it was his invariable rule to do absolutely nothing for a week. He hired Frank Conners to cook for that week and generally make himself useful, while Professor Micheals slept.

During the second week, Micheals would wander around, look at the trees and fish. By the third week he would be getting a tan, reading, repairing the sheds and climbing mountains. At the end of four weeks, he could hardly wait to get back to the city.

But the resting week was sacred.

"I really wouldn't bother you for anything small," Conners said apologetically. "But that damned rock melted two inches off my spade."

Micheals opened both eyes and sat up. Conners held out the spade. The rounded end was sheared cleanly off. Micheals swung himself off the couch and slipped his feet into battered moccasins.

"Let's see this wonder," he said.

The object was lying in the ditch at the end of the front lawn, three feet from the main road. It was round, about the size of a truck tire, and solid throughout. It was about an inch thick, as far as he could tell, grayish black and intricately veined.

"Don't touch it," Conners warned.

"I'm not going to. Let me have your spade." Micheals took the spade and prodded the object experimentally. It was completely unyielding. He held the spade to the surface for a moment, then withdrew it. Another inch was gone.

Micheals frowned, and pushed his glasses tighter against his nose. He held the spade against the rock with one hand, the other held close to the surface. More of the spade disappeared.

"Doesn't seem to be generating heat," he said to Conners. "Did you notice any the first time?"

Conners shook his head.

Micheals picked up a clod of dirt and tossed it on the object. The dirt dissolved quickly, leaving no trace on the gray-black surface. A large stone followed the dirt, and disappeared in the same way.