The fellows returned the salutation hastily.
"Say, Balcom," hastened one of them, "some one is on your trail, shadowing you."
Paul was startled and furious, but in this emergency it was Dora who thought out the plan of action.
"In a taxicab?" she repeated, as the others told what they had seen outside. "Listen to me, Paul. Go to the window and show yourself. Then leave the house. This fellow Locke will investigate—and we'll tend to the rest."
Paul moved to the window, opened it, and stepped out on a small balcony. Dora slipped to his side and for a moment they stood there gazing apparently at the view of the river. Then they re-entered the apartment.
"Now go, Paul," said Dora. "Whoever this fellow is, we'll handle him."
Paul started to get his hat, then stopped and from his pocket drew out a small package.
"I was going to use this elsewhere," he said, "but it might come in handy to—"
Dora reached for the package, but Paul withdrew it hastily.
"Careful, Dora," he admonished. "There's a small gas-bomb inside."