Perilous days on the Mississippi followed, when Blake and Joe took pictures of the flood, and later they were sent to Panama to make views of the digging of the big canal.

Mr. Hadley was a producer who was always eager for new thrills and effects. And when he thought he had exhausted those to be secured on the earth, he took to the ocean. And in "The Moving Picture Boys Under the Sea," the book that immediately precedes the present volume, will be found set down what happened to Blake and Joe when, in a submarine, they took views beneath the surface.

They had not long been home from their experiences with the perils of the deep when they were engaged to make views for "The Dividing Line," with its battle pictures, more or less real.

"What's the matter? What happened? Is any one hurt?" cried Mr. Hadley, as he ran toward the scene of the explosion, followed by Blake and Joe. They could see, by a large cloud of smoke, that something extraordinary had occurred. The figures of several men could be noted running about.

"Is anybody hurt?" demanded the producer again, as he and the two boys reached the place. "I'll send the ambulance, if there is." For when a film battle takes place men are often wounded by accident, and it is necessary to maintain a real hospital on the scene.

"I don't believe any one's hurt," remarked Mr. Robertson, who did juvenile leads.

"Unless it might be C. C.," remarked Mr. Levinberg, who was usually cast as a villain. "And small loss if he was laid up for a week or so. We'd be more cheerful if he were."

"Is C. C. hurt?" asked Joe.

"No; but I guess he's pretty badly scared," answered Mr. Robertson. "After this I guess he'll have more respect for a smoke bomb."

"Was that what exploded?" asked Mr. Hadley.