"Rather," Teddy agreed. "But our calculations told us that Varrhus had reached and was using a temperature within two degrees of that in the center of his ice cake. And right next to that temperature he had a very high one, as evidenced by the plume of steam."
"I can't see how you got anywhere," said the reporter hopelessly. "I'm all mixed up."
"It's very simple," said Teddy cheerfully. "On one side of a wall the man had what amounted to a thousand and some odd degrees below zero. On the other he had probably as much above zero. Evelyn—Miss Hawkins, you know—made the suggestion that solved the problem. She showed us this."
Teddy picked up what seemed to be a square bit of opaque glass.
"Smoked glass?"
"Yes, and no." Teddy smiled. "You can't see through it, can you?"
"No."
"Come around to this side and look."
The reporter made an exclamation of astonishment.
"It's clear glass!"