Nothing happened.
As the seconds ticked by and still there was no explosion, the professor began to wilt. He gazed desperately at his wife who looked as dismayed as he.
“My dear, something seems to be wrong. Are you sure you saw the signal? Perhaps Webb has not yet dropped the mine.”
“I saw the signal. The lantern was waved three times.”
The professor made several adjustments on his machine, and again struck the musical note. But there was no explosion. Enjoying his discomfiture, Salt and Penny grinned from ear to ear.
“You did something to the machine!” the professor accused them furiously. “You came here and tampered!”
“We’ve not been near this place tonight until a moment ago,” Penny retorted. “The truth is, you weren’t able to explode Mr. Johnson’s mine!”
“That’s not so!” The professor’s face now was red with anger. “Something has gone wrong, but that doesn’t prove my machine is a failure. We’ll have another test.”
“I’m not sure that I shall be interested,” Mr. Johnson said quietly. “I’ve been thinking the matter over and there are so many hazards—”
“I’ll make you an especially good offer,” the professor declared, flipping the canvas cover over his machine. “Furthermore, we will have the test tonight. I guarantee to explode the mine before you leave here.”