"Where are you taking me?" he cried, fearfully.
"Oh, you're beginning to recognize the route now, are you? Yes, we're going back to the place you came away from in such a hurry not so very long ago!"
"You were there!" said Hallo; suddenly, "I thought I knew your voice—in the boathouse! That was you who came in the launch?"
"I don't have to answer," said Dick. "Hurry along! You slow up when you talk. And your talk isn't interesting enough to make it worth while to delay."
"I—"
Whatever Hallo meant to say was never finished. For suddenly the ground shook, and there was a dreadful roar. A huge flash lit up the sky, and behind them bedlam seemed to break loose. There was a succession of reports, like repeated volleys of rifle fire, and sometimes a louder roar.
"There goes the arsenal, so you can quit worrying," said Dick. "Even if I let you go now, you couldn't prevent that, could you? Oh, I knew what you were driving at, all the time!"