"Of course you'll do it," the robot said firmly. "Nobody's ever refused yet. And don't bicker with me or you'll get me confused and I'll have to take another jolt of voltage. Then there's no telling how confused I'll be. My memory gives me enough trouble when I temporalize. Time-travel always raises the synaptic delay threshold, but the trouble is it's so variable. That's why I got you mixed up with Ivan at first. But I don't visit him till after I've seen you—I'm running the test chronologically, and nineteen-fifty-two comes before fifteen-seventy, of course."
"It doesn't," Martin said, tilting the glass to his lips. "Not even in Hollywood does nineteen-fifty-two come before fifteen-seventy."
"I'm using the Kaldekooz time-scale," the robot explained. "But really only for convenience. Now do you want the ideal ecological differential or don't you? Because—" Here he flourished the red ribbon again, peered into the helmet, looked narrowly at Martin, and shook his head.
"I'm sorry," the robot said. "I'm afraid this won't work. Your head's too small. Not enough brain-room, I suppose. This helmet's for an eight and a half head, and yours is much too—"
"My head is eight and a half," Martin protested with dignity.
"Can't be," the robot said cunningly. "If it were, the helmet would fit, and it doesn't. Too big."
"It does fit," Martin said.
"That's the trouble with arguing with pre-robot species," ENIAC said, as to himself. "Low, brutish, unreasoning. No wonder, when their heads are so small. Now Mr. Martin—" He spoke as though to a small, stupid, stubborn child. "Try to understand. This helmet's size eight and a half. Your head is unfortunately so very small that the helmet wouldn't fit—"
"Blast it!" cried the infuriated Martin, caution quite lost between Scotch and annoyance. "It does fit! Look here!" Recklessly he snatched the helmet and clapped it firmly on his head. "It fits perfectly!"
"I erred," the robot acknowledged, with such a gleam in his eye that Martin, suddenly conscious of his rashness, jerked the helmet from his head and dropped it on the desk. ENIAC quietly picked it up and put it back into his sack, stuffing the red ribbon in after it with rapid motions. Martin watched, baffled, until ENIAC had finished, gathered together the mouth of the sack, swung it on his shoulder again, and turned toward the door.