years old. Then, working them out on lines of classification, and resorting to a few imaginative guesses, he stumbled on the key to the whole thing!"
Andelman sat in thoughtful silence, at the end of this speech. Kestner waited for several moments: then he swung unctuously back to his theme.
"Any code can be worked out in that way. There isn't a cipher-code in the Service, land or sea, that isn't vulnerable to the expert, once he has time enough and reason enough for working it out."
Andelman's slowly awakening smile was one of patient forbearance.
"You are altogether wrong. How could a foreigner, for example, derive any earthly good from a knowledge of the Navy Department's new wireless Clock Code?"
"Why not?" asked Kestner.
"Because the significance of every cipher depends not only on the hour of the day, but on the minute of that hour, at which it is despatched, the same message, I mean, sent at twenty different times during the day may mean twenty entirely different things. And the chronometrical determination of each cipher value, again, is protected by our adaptation of the Hovland Keyboard Cipher,—you've
