his unused plate. I rose and, leaning over him, stared down at the curious inscription, which ran as follows:
584 C2 13 127 36 31 4 17 21 41
DOUGLAS 109 293 5 37 BIRLSTONE
26 BIRLSTONE 9 47 171
“What do you make of it, Holmes?”
“It is obviously an attempt to convey secret information.”
“But what is the use of a cipher message without the cipher?”
“In this instance, none at all.”
“Why do you say ‘in this instance’?”
“Because there are many ciphers which I would read as easily as I do the apocrypha of the agony column: such crude devices amuse the intelligence without fatiguing it. But this is different. It is clearly a reference to the words in a page of some book. Until I am told which page and which book I am powerless.”
“But why ‘Douglas’ and ‘Birlstone’?”
