A startled exclamation burst from the younger man's lips. He dropped to his knees. Scrutinized the puddle of glass.
But the scientist pulled him erect again.
"My instruments!" he ordered in a voice that trembled. "Quick! I must make tests—"
For half an hour he worked. And when at last he straightened, complete confidence gleamed deep in his eyes.
"Is it—"
Professor Duchard nodded.
"It is. That was the secret, my boy. The secret we sought but could not find. The time mirror is merely a special glass which has been subjected to a terrific electrical discharge, then silvered. That piece on the floor is worthless, of course; too many elements were uncontrolled.
"But knowing the formula as we do; knowing exactly what we are searching for and how to prepare it, I would stake my reputation that we can duplicate the mirror Adrian Vance sent to Elaine."
Mark's eyes were gleaming. His jaw hard.
"Then do it!" he commanded.