“But why do you want me to do it? You mean to substitute Mr. Johnson’s mine for one of the others?”
“That’s the ticket,” chuckled the photographer. “Maybe my guess is wrong, but I have a sneaking suspicion if we use one of the professor’s own mines, it will fail to explode.”
“The mine has to be doctored with that powder we saw Webb use!”
“That’s my theory, Penny.”
“But maybe the other mines have already been treated.”
“That’s a possibility,” Salt admitted thoughtfully. “No way of telling that, because the hole would be covered so skillfully. We’ll have to take a chance on it.”
While Salt held the lantern, Penny scratched Mr. Johnson’s initials on the metal covering of the mine. Skilled in art, she was able to copy them fairly well.
“They don’t look exactly the same,” Salt said, comparing the two, “but they’re good enough to get by unless Mr. Johnson becomes very critical.”
Quickly they moved the two mines, placing Mr. Johnson’s well to the back of the room, and leaving the substitute exactly where the other had been.
“Well, that job is done,” Salt chuckled. “Unless I miss my guess—”