"Look out!" cried Sammy. "You may get shot!"
"No danger!" laughed the young man. "I fancy you boys set off the flashlight, and there isn't another."
"Flashlight!" cried Sammy.
"Yes, that was what made the smoke and explosion," said Mr. Houghton. "You touched the spring that worked the electric battery, and the current set off some flashlight powder in a box. It did make quite an explosion, I fancy."
"But what was flashlight powder doing up here?" asked Mr. Jessup.
"I was trying to get some night photographs of bats," explained Mr. Houghton. "You see all this apparatus is just some photographic cameras, set to work automatically. I fancy I have the pictures of you boys on the plate, instead of the bats," and he smiled at the three chums.
"Photographs!" cried Sammy.
"Cameras!" exclaimed Bob.
"Aren't these things telescopes?" asked Frank.