“There is a hammer in the next room on the shelf.”

“I’ll get it.”

Leaving Mr. Starleigh leaning against a table, Bob rushed out into the operating-room. He found the hammer, and also brought with him the valuable lenses, which he knew his employer greatly prized.

With all his force he began to batter on the door. At first it resisted his efforts, but finally with a crash one of the panels gave way.

Then another panel was knocked out, and, with savage energy, Bob attacked the middle strip.

His blows fell thick and fast. At last came a crash, and the top of the door was smashed into several parts.

“Just in time,” cried Mr. Starleigh. “See, the whole operating-room is in flames!”

The hall-way seemed to be now quite free from smoke. Bob leaped through the opening he had made, and helped his employer to follow.

“Hullo! what’s up here?”

It was a fireman who asked the question.