“But the mine I supplied is at the bottom of the lake and it failed to go off,” Mr. Johnson said.
“First, we will talk to Webb and learn exactly what happened,” the professor said, taking him by the arm. “I know there is a logical explanation for the failure.”
Glaring at Penny and Salt, he shooed everyone out of the cabin, locking the door.
“My dear,” he said to his wife, giving her a significant look, “take Mr. Johnson to the house while I find Webb. I’ll be with you in just a minute.”
The professor went hurriedly down the beach while Mrs. Bettenridge and Mr. Johnson walked slowly toward the rooming house. Penny and Salt remained beside the cabin until everyone was beyond hearing.
“Well, our trick worked,” Salt chuckled, “but if we aren’t careful, the professor will pull off a successful test yet and ruin all our plans.”
“He and Webb are certain to examine the mines and discover the one with Mr. Johnson’s initials still in the shack. Then they may convince Mr. Johnson there was a mix-up, and go ahead with another test which will be successful.”
“We’ve got to do something,” Salt muttered. “But what?”
“I know!” Penny exclaimed. “I’ll telephone Dad and have him come here right away with Major Bryan!”
“Good!” approved Salt. “I’ll stay here and hold the fort while you telephone. Tell your father to step on the gas, because we’ve got to move fast to queer Professor Bettenridge’s game.”