Kennedy shrugged. “I don’t know. Riley promised to call up the next chance he got.”
“Why not go over to Dexter’s?” suggested Hastings.
“She can’t be there,” returned Kennedy. “If she was, Riley would have had a chance to make a second call. Therefore I reason that she must have gone away after she had seen the clerk and when Shelby appeared. I think I’ll stay here awhile, until I hear again—especially as I have nowhere else to go,” he decided, pulling out the cipher from his pocket again. “We may hear some more about Shelby and his schemes.”
Kennedy had now fallen into an earnest study of the peculiar cryptogram which we had discovered.
“I suppose you’ve noticed that there’s no figure above five in it,” he remarked to me, looking up for an instant from several sheets of paper which he was covering with a hopeless jam of figures and letters.
“I had not,” I confessed. “What of it?”
“Well, I’ve tried the numbers in all sorts of combinations and permutations. They don’t work. Let me see. Suppose we take them in pairs.”
For several moments he continued to figure and his face became continuously brighter.
“There are six pairs of 33’s,” he remarked, almost to himself. “Now, it’s well known that the letter ‘e’ is the most commonly used letter. That’s the starting point usually in working out a cipher. Wait—there are eight ‘15’s’—that must be ‘e.’ Yes, the chances are all for it. Now what letter is 33, if any?”
He appeared to be in a dream as he recalled from his studies of cryptograms what were the probabilities of the occurrence of the particular letters. Suddenly he exclaimed: