“I’ll be careful,” pledged the stranger, and to Tom’s amazement with a deft expert touch he dislodged the cap of one of the glass tubes. “I say, my friend,” he added, gazing down into the cup critically, “you’d get much better action if you’d mix in some fine brass filings here. The old stuff is pretty well corroded.”
“I had noticed that,” said Tom, “and have sent to the city for new material.”
“There’s another point worth your attention,” resumed the man, pointing up at the secondary circuit. “A double coil to that condenser would strengthen your current.”
Tom stared at the speaker in a vague way. He was a good deal surprised and also suspicious at the facility with which this avowed seeker for information exhibited a profound knowledge of the very subject under discussion.
“You seem to know something about it,” observed Tom.
The man did not reply. He busied himself with a fixed and calculating glance through the roof skylight up at the metal nets and spirals.
“Very good,” he said, half aloud, “and kept in very fair order, too.”
“I’m glad to hear you say it, Mr ——?”
“I am expecting a friend who will introduce us,” said the stranger, with a peculiar smile. “Ah, there he is now.”
He moved to the window, and in quite a friendly fashion waved his hand to an occupant of an automobile that had just driven up from the beach road.