“Yes, yes,” agreed the man.
Inside the closet, Penny and Salt breathed easier.
“Let’s get on with the demonstration,” the professor urged with sudden impatience. “Load the mine onto the boat, Webb. Go out to the center of the lake. Then when you have dropped it, give the usual signal.”
“When everything is okay, I’ll wave my lantern three times,” Webb agreed.
The mine was trundled out and the shack became dark. However, Salt and Penny did not dare come out of hiding until they heard Webb start the motor of the boat.
“The coast is clear,” the photographer then reported, peering out a crack of the outer door. “Webb has gone, and the professor and Mr. Johnson are walking up to the cabin.”
From the beach, Penny and Salt watched the boat moving slowly across the water. Presently the craft stopped, and the mine was heaved overboard. The pair waited, but there was no signal from Webb. Nor did his boat move away from the locality where the mine had been dropped.
“Why doesn’t he wave the lantern?” Penny fretted.
“He’s waiting deliberately, and for a purpose,” Salt declared. “Why not amble up the hill and watch the professor perform?”
“Not a bad idea,” agreed Penny.