"All right," said the old man.
The first they had heard of the strangers from outer space was when the new ultra short-wave frequencies were used. Professor Kennicot of Palmira University was the first to find how to generate and control them. He tried to transform the wavelengths upward to a range either auditory or visual but for some reason power was lost in the process.
Apparently he gave them a sufficient jolt with extra voltage, however, because they were picked up by the strangers in outer space as a signal. The heaviside layer did not stop these wavelengths.
Professor Kennicot was startled one day when he heard, or thought he heard, a soundless voice in his mind. It said:
"Interesting. We didn't know there was life on your planet or in your solar system."
Professor Kennicot shook his head and looked around. Nobody was in the laboratory.
"Of course," said the voice, "We detected atomic radiations from the area, but Zeetal thought it might come from your sun. Tell us, please, are you a Grade Three society?"
"My God," muttered Professor Kennicot. "I'm having hallucinations."
"There seems to be some difficulty establishing telepathic communication," came the puzzled thought. And then, after a pause, "Could it be we're in communication with creatures of zero grade?"