The light from above was diminishing; outside sounded the roar of home-going traffic.
"Well, we must go home," said Professor Young. "There's a hard and interesting day ahead of us to-morrow, and I want to read Orling's new work on matrices before we begin chipping at the amber."
Young turned on his heel and strode toward the locker at the end of the room where he kept his coat and hat. Betty, about to follow him, was aware of a hand on her arm, and she turned to find Marable staring at her.
"I saw them, too," he whispered. "Could it have been just imagination? Was it some refraction of the light?"
The girl paled. "I—I don't know," she replied, in a low voice. "I thought I saw two terrible eyes glaring at me from the inky heart. But when father laughed at me, I was ashamed of myself and thought it was just my fancy."
"The center is liquid, I'm sure," said Marable. "We will find that out soon enough, when we get started."
"Anyway, you must be careful, and so must father," declared the girl.
She looked at the block again, as it towered there above them, as though she expected it to open and the monster of the coolies' imagination leap out.