He located MacVightie and Lanson; and, thereafter, at a safe distance, did not lose sight of them. MacVightie's memory for faces would hardly be over-rated if credited with being able to bridge a matter of some twenty-four hours, particularly as MacVightie had evidenced unusual interest in the occupant of the room on the first landing over a certain ill-favoured saloon the night before! The Hawk, therefore, was unostentatiously attentive to MacVightie's movements; so much so that, when No. 17 pulled in and MacVightie and Lanson boarded the chair car at the rear of the train, the Hawk, when No. 17 pulled out, quite logically boarded the smoking car at the forward end.
The Hawk chose the most uncomfortable seat in the car—the rear seat with stiff, upright, unyielding back, that was built against the wash-room—and, settling himself down, produced his notebook and pencil. The water-cooler could be quite confidentially trusted not to peer over his shoulder!
On the second page of the notebook—the first having been devoted to the sketch of Bald Creek Station—-the Hawk, as he had taken it from the sounder, had written this:
“wtaz qxpetlkhu wkmuh hdtlq gvhmmpy hqltvd df rmnluvpo nfkhomovfdh gvkerkmmawrq fljkwte dvsoedtdqqh mgfdoifk rxqkuvwruh gsruwmtdoo ommtlqhvksol foghvklst rvrzqmqxpe mkhurqjkh hvdbfvkdzc mnvohrtpqg hutzklwkj hkdqm mo g v pdlqlfxoq uhgpifthglxg pkhlmfj kwhttwb hv d p q g kdrllu eomosdfnhta shqkjvlyhtg mwdlomruhgegf orwmpqk hvwtzrwk mmrxvddg iqggrqo odusnvrx wmfkriu hkvhuymt hixqljtg wrqpxpeh houwkdmd gwsxws vdexmuooh wtjqlqklmp”
The Hawk tore out a page from the back of the notebook, and set down the letters of the alphabet in a column. Opposite these he painstakingly set down another column of letters. After that the Hawk worked slowly. It was not quite so simple as it looked—not merely the substitution of letters in a different order of rotation. Nor, apparently, from the Hawk's observations as he muttered to himself, were all messages to be deciphered alike—the code appeared to possess within itself an elasticity for variation.
“At four... key letter changed... stroke!” muttered the Hawk. “N-u-m-b... pass three... e-r-t-h... stroke one....”
The Hawk's notebook, closed, was reposing idly on the window ledge and the Hawk was lighting another cigarette, as the conductor came down the aisle. The Hawk presented the return stub of a ticket to Selkirk. The conductor punched it, and passed on—and the Hawk picked up his notebook again.
Again he was interrupted—and again. The water-cooler, after all, was not proving an unmixed blessing. It seemed as though every man in the car were possessed of an inordinate thirst. They were well on toward Selkirk when the Hawk finally completed the deciphering of the message.
It now ran: