Jan. 10, 1940--Morton had written--Discovered today what is unquestionably the tomb of a Sumerian king. Located in a hillside. Cut out of solid rock. Landslide centuries ago had covered entrance. But even more important, in my opinion, than the tomb is the discovery of the strange metal box that we found in a niche at the back. We are unable to determine the metal of which the box is constructed. It is covered with mould but shows no sign of rust or corrosion, which is exceedingly unusual, for this tomb dates back into the past for at least six thousand years. "Jan. 12, 1940. Box very heavy--must weigh more than a hundred pounds. Frankly, aside from its archeological interest, I am curious to know the contents of this box. There is a possibility of gold or gems. Guess I'm human after all, to be thinking about wealth. Am writing full details to the museum. "Jan. 15, 1940. Unable to open box. Must have cunning combination lock. Also unable to decipher inscription on it. Don't know this form of writing. No record of it anywhere. This is exceedingly unusual. A completely forgotten language rediscovered." Rocks Malone went through the notes, reading swiftly, searching, hoping for a clue. Outside in the night death was stalking. And there was a possibility that the clue to the death lay here, in the notes of the dead archeologist. Penny came in. He went to meet her. She flew to his arms. "It's awful outside," she whispered. "Thousands of people must have heard the news broadcast. Half of them are trying to get to the theater where all those people were killed. The others are trying to get away. Oh, Rocks, have you discovered anything." He shook his head. She looked again at his unshaven, haggard face, and said nothing. He went back to the notes Morton had left. With Penny helping, he went through them, down to the last page. "It's no use," he groaned. "Morton didn't know anything about the thing that was in that damned box." Then he turned the last page. Morton had written that page only yesterday, the day he died. "Sept. 21, 1940. Succeeded in opening the box today. As I suspected it was closed by a combination lock. Deucedly clever thing, that lock. Not like any lock in use today. Patent rights on it might provide the museum with some of the cash it so badly needs. "To my great astonishment, and regret, when I opened the box, I found it empty." Rocks Malone started at the words Morton had written. Penny had been reading over her shoulder. He heard her catch her breath. EMPTY! The single word seemed to leap out at him. How on earth could Morton make a mistake like that! There was another line of writing. "Weighed box. Find that it weighs nine pounds less than it did when I brought it here." In the fleeting flash of a second, Rocks saw the whole picture. Or almost all of it. There were parts that needed clearing up. But he knew at last the real significance of the fact that Morton had weighed the box a second time.