With his knife he cut away from the envelope the loose flap and the back, leaving an oblong piece of opaque, manila paper, marked off in those queer blank spaces. Then Bob began to cut out the spaces along the black border lines until he had a piece of paper containing fifteen oblong holes. The holes were at irregular places, and arranged in lines.
There was one space on the first line, two on the second, three on the third, five on the fourth and two each on the fifth and sixth lines.
“It’s getting more complicated than ever!” sighed Harry.
“On the contrary it’s getting clearer and clearer,” cried Bob. “Give me the cipher,” and he reached for it. “How many lines in it, Ned?”
“Just six,” was the answer.
“Exactly the number of lines represented by these cut-out spaces. Now look!”
Bob placed the piece of envelope over the parchment containing the seemingly meaningless message. Only the words now showed that could be read through the cut-out openings. All the others were covered by the opaque manila. And these words stood out like a message in flame.
“Listen!” read Bob:
“Dig ten feet due east and ten south of Red gate post in buttercup lot.”
For a moment no one spoke. Then Ned cried: