"There it goes again!" exclaimed Alice.
"Look!" cried her sister.
She pointed through the open window, and as the girls peered out they saw the top of the hill fly upward in a shower of dirt and stones.
Once more the deep boom sounded.
"It's a big gun!" cried Alice. "I remember, now. Mr. Pertell said he wanted pictures of a siege of a fort, and he sent for a big gun to get explosive effects. Come on over!"
"And be blown to pieces?" objected Ruth. "Don't dare go, Alice DeVere!"
"Oh, come on! There's no danger. Russ is going to make the films. I guess they're just trying it now. It's too late to make good pictures. Come on."
"I'll go," offered Estelle. "I don't mind the noise."
Ruth declined to go, so the other two girls set off. On the porch they met Russ and Paul, who confirmed their guess that it was a big siege gun which Mr. Pertell had sent to New York to get, so he might show the effect of explosive shells.
"I'm going to film some to-morrow," Russ said.