“Watch closely,” said the professor again. “There comes the first of it.” Tubby saw a row of little digits start on the tape. The first three were 154. Then after the comma began a string of ciphers; after each three ciphers was another comma. The moving tape carried this endless row of little ciphers swiftly under Tubby’s nose. He stared at them fascinated. Faster and faster they flew by as the roll of tape wound up on the spindle the professor was turning. For half an hour he turned briskly. Then the row of ciphers stopped just as the other end of the tape fluttered off the unwinding spindle.
The professor leaned against the wall, breathing hard.
“That—was—the—number,” he gasped.
Tubby blinked. “What—what number was it?” he asked finally.
The professor recovered his breath and sat down again in his chair wearily.
“It was one hundred and fifty-four zin-tillions,” he answered. “The largest number that has ever been written down. Wrote it down this afternoon.”
“Yes,” said Tubby. “It was a big number.”
The professor pulled at his side-whiskers thoughtfully. “We must get on,” he said. “Now you understand how far the stars are away. And how fast light travels. That brings us to my Light Machine.”
Tubby sat up with interest. “To the Light Machine. Yes, go on.”
“As you can see,” the professor continued. “I know all about Light—I am its master. No one in the world knows as much about Light as I do. And only one man in the world thinks he does.” The professor’s eyes gleamed vindictively. “Ah, how I hate him, that man!”