From the inner photography room came a terrified scream. Elda Hunt, her face white with fear, appeared in the doorway.

“You!” she exclaimed, recovering from the shock of Penny’s unexpected entry.

“Now take it easy, Elda,” Penny advised, brushing dirt from her sweater. “I was only experimenting.”

“Experimenting!”

“I wanted to see if it would be possible for a person to get into this room through the skylight. It is possible!”

“You don’t say!” Elda commented sarcastically. “I’ll bet you were the one who pulled that stunt in the first place!”

“How ridiculous!” Penny was irritated. Not wishing to discuss the matter, she turned and walked out of the photography room.

In the corridor she met Salt Sommers who stopped her to ask when they were to visit Professor Bettenridge in the country.

“Eight o’clock tonight, if you’re willing to go,” Penny said eagerly. “I very much want to see the professor demonstrate his ray machine for Mr. Johnson.”

“And I want to find out what became of my camera,” Salt added grimly. “Is it a date?”