And had those papers been taken aboard the Wyvern it had not been very long before the simplicity of the cipher had been discovered by anybody trained in code work.
For, in spite of its surface complexity, the cipher was a singularly simple one, even a stupid code, based on simple principles long known and understood in all of their hundreds of variations.
And all such ciphers, granted time and patience, could be solved by the same basic principles. The only function of that kind of code was to so multiply its intricacies and variations that, with a time limit for delivery understood, measures could be taken at the other end to minimize the effect of discovery, the elapsing of the time limit serving as an automatic warning that message or messenger were under forcible detention within the enemy's lines.
Yes, it had been a stupid cipher, and an easy one.
A trained man would have solved it in half the time he had required.
Nothing about the message remained really obscure except the Japanese dancing girl playing with her butterfly and fan, and the lack of information concerning the "fleet" at anchor or cruising near "Lough Swilly" on the Irish coast.
As far as the fleet was concerned, Guild was very confident that he understood. The whereabouts of the British battleship fleet was not known, had been carefully guarded. Without a doubt Lough Swilly was its rendezvous; and the German spy system in England had discovered it and was sending the information to Berlin with a suggestion that submarines "follow the birds," i. e., take that dotted course around the northern Scottish coast, slip south into Lough Swilly, and attack the first line of battle squadron where it had been supposed to lurk in safety, awaiting its call to action. That was as clear as daylight, but the Japanese figure he could not understand.
He was utterly unable to sleep. After an hour's staring into the darkness he rose cautiously, opened the stateroom door and stepped into the lighted corridor.
Here he lighted a cigarette against regulations and began to pace up and down.