The Camera Chap threw open the window. “Sure; come on in,” he said. “There’s no reason for you to stay out there any longer.”

“The picture is finished?”

Hawley laughed ironically. “Yes, it’s finished, all right—completely finished. Take a look at it.” As he spoke he held up the square of wet glass.

“I don’t know much about this sort of thing,” said the navy man, taking the negative gingerly, and holding it against the light of the ruby lamp. “It’s always been a mystery to me how you fellows can tell at a glance whether a negative is a good or a poor one. The few I’ve handled all looked pretty much alike to me. They all—why, hello! There doesn’t seem to be anything on this plate. I can’t see a blessed line. Anything wrong with it, old man?”

The Camera Chap smiled ruefully. “No, there’s nothing wrong with it at all,” he said. “It’s a perfectly good plate—only, unfortunately, it’s never been exposed.”

“Never been exposed?” Ridder repeated, too ignorant of photographic terms to grasp immediately the full significance of this announcement. “Do you mean that the picture is spoiled?”

“I mean that the picture was never there,” the Camera Chap replied. “Something was wrong with the shutter of my camera. It couldn’t have been open when I set off the flash light. Can you beat that for tough luck?”

“Too bad,” the lieutenant murmured. “I guess the old man will be disappointed when he hears this. I don’t know what this picture business is all about, since neither of you has seen fit to take me into the secret, but I gathered from the skipper’s manner that he was dead anxious to get the snapshot.” He glanced at the Camera Chap anxiously. “Does this mishap make much difference, old man? Can’t you take the picture over again?”

The question brought a sardonic smile to the other’s face. “I suppose that’s what I’ll have to do—take it over again,” he said presently, the smile giving place to an expression of grim resolution.

Just then they were interrupted by a knock at the door. The two men exchanged a questioning glance, and the Camera Chap’s hand went to his coat pocket, and grasped the revolver it contained. Lieutenant Ridder’s weapon was still in his hand.