In a sudden frenzy of horror I pawed my way around the cage to where John still knelt. As I reached him he jerked his head in a numb way as he croaked, "It's a diamond, sir! The professor's!"
"But how?" I implored. "How can it be? There's no way into this thing. Perhaps he was working here, and the stone came loose from its setting. He couldn't have dropped it after the cage was completed."
"It's his diamond, sir," intoned the old man, dully. "I know it is."
Then a sudden unreasoning terror filled me. I shrank away from that shining box. It seemed to be mocking me, gloatingly, malevolently.
"Quickly!" I threw at the aged couple. "Let us get out of here! Now! At once!" They needed no second urging. I knew that they felt as I felt: the laboratory was a sepulcher!
Five minutes later I was guiding my car over the narrow road to town. I did not pause until I drew up at police headquarters. I suppose my appearance was distraught, for I was ushered into the presence of the chief without delay. In a few moments I had poured out my story. He listened with a polite calmness I found almost maddening. Leaning back in his chair, he reviewed, audibly, the facts.
"Some twenty-odd years ago your friend, Professor Wroxton, married. He was so absorbed in the pursuit of some weird invention that he neglected his bride. She ran away with another man. This man deserted her, and disappeared. The professor found her many months later, in desperate health. Shortly afterwards she died. Your friend tried to trail the man, but failed. Shocked and saddened beyond measure, he retired to a place known as The Grange."
He suddenly straightened up in his seat, and pointed at me a thick forefinger.