The next day had been set for filming the scenes with the big gun in them. Contrary to expectations, no pictures could be taken, as the throwing up of the earthworks had not been finished. But a number of men from both "armies" were set to work, and as it afforded good practice for the militia they were called on to dig trenches, throw up ridges of earth, and go through other needful military tactics. The girls had no part in the scenes with the big gun, except that, later on, they were to act as nurses in the hospital tent. On top of the hill a force of Confederates would be stationed, and they were to reply to the fire of the big gun. Of course, when the projectiles struck the hill the soldiers would be a safe distance away, but by means of trick photography scenes would be shown just as if they were sustaining a severe bombardment. "Is everything ready?" asked Mr. Pertell, a few days after the setting up of the big gun, during which interval a sort of fort had been constructed on the hill and a redoubt thrown up. "I think so," answered Russ. "We couldn't have a better day, as far as sunshine is concerned. I'm ready to film whenever you are." "I'll give the word in a minute. Paul, you're in charge of a detachment of Union soldiers that storms the hill as soon as the big gun has silenced the battery there." "Very well, sir." The big gun rattled out its booming challenge and was replied to by volleys from the rifles of the Confederates on the hill and by their field artillery, which they hurriedly brought up. Shot after shot was fired, and one after another the Confederate cannon were disabled. They were blown up by small charges of powder put under them, set off by fuses lighted by the Confederates themselves, but this did not show in the picture, and it looked as though the Southern battery was blown up by shots from the big gun. "All ready now, Paul! Lead your men!" yelled the director, who was standing near Russ and his camera. "Rush right up the hill. Stop firing here!" he called to those in charge of the big gun. But something went wrong, or some one misunderstood. As Paul was charging up the hill at the head of his little band, Russ, turning his head for an instant, saw a man about to pull the lanyard of the big gun. "Don't shoot! Don't shoot!" he yelled. "It's aimed right at Paul and his fellows!" But Russ was too late. The man pulled the cord. There was a deafening roar, a cloud of smoke, a sheet of fire, and a black projectile was sent hurtling on its way against the hill, up the side of which Paul was climbing with his soldiers. CHAPTER XXI THE BIG SCENE Nothing could be done! No power on earth could stop that projectile now until it had spent itself, or until it had struck something and exploded. Horror-stricken, those near the big gun looked across the intervening space. How many would survive what was to follow? The man who had pulled the lanyard sank to the ground, covering his face with his hands.