A third sum of a thousand pounds was offered for a list of the postal sections on the British front, with the name, initials and rank of a really good and reliable British soldier in each section who was prepared to receive and answer correspondence.

Fairbairn chuckled and observed: 

“I think Herr Zimmermann might be provided with a number of such good and reliable soldiers selected by our General Staff,” and he added with a truculent snort, “We could do with that sum of a thousand pounds here.  You must put in a claim for it, Hillyard.  Otherwise they’ll snaffle it in London.”

Fairbairn, once a mild north-country schoolmaster, of correct phraseology and respectable demeanour, had, under the pressure of his service, developed like that white sheet of notepaper.  He had suffered

               “A sea-change
     Into something rich and strange”

and from a schoolmaster had become a buccaneer with a truculent manner and a mind of violence.  London, under which name he classed all Government officials, offices, departments, and administrations, particularly roused his ire.  London was ignorant, London was stupid, London was always doing him and the other buccaneers down, was always snaffling something which he ought to have.  Fairbairn, uttering one snort of satisfaction, would have shot it with his Browning.

“Get it off your chest, old man,” said Hillyard soothingly, “and we’ll go on with this letter.  It looks to me as if——­” He was glancing onwards and checked himself with an exclamation.  His face became grave and set.

“Listen to this,” and he read aloud, translating as he went along.

“Since the tubes have been successful in France, the device should be extended to England.  B45 is obviously suitable for the work.  A submarine will sink letters for the Embassy in Madrid and a parcel of the tubes between the twenty-seventh and the thirtieth of July, within Spanish territorial waters off the Cabo de Cabron.  A green light will be shown in three short flashes from the sea and it should be answered from the shore by a red and a white and two reds.”

Hillyard leaned back in his chair.

“B45,” he cried in exasperation.  “We get no nearer to him.”

“Wait a bit!” Fairbairn interposed.  “We are a deal nearer to him through Zimmermann’s very letter here.  What are these tubes which have been so successful in France?  Once we get hold of them and understand them and know what end they are to serve, we may get an idea of the kind of man obviously suitable for handling them.”

“Like B45,” said Hillyard.

“Yes!  The search will be narrowed to one kind of man.  Oh, we shall be much nearer, if only we get the tubes—­if only the Germans in Madrid don’t guess this letter’s gone astray to us.”

Hillyard had reflected already upon that contingency.

“But why should they?  The sleeping-car man is held incomunicado.  There is no reason why they should know anything about this letter at all, if we lay our plans carefully.”