to find him; he may do a lot of mischief before that comes about." Sage gazed meditatively at his finger-nails, a habit of his. "On the other hand," he continued, "if you know your man, you can watch him and generally find out what he's after. Better a known than an unknown danger," he had added oracularly.
"I'm afraid they wouldn't endorse that doctrine at Scotland Yard," smiled Mr. Llewellyn John.
"Scotland Yard is a place of promoted policemen," replied Sage, "regulation intellects in regulation boots."
Mr. Llewellyn John smiled. He always appreciated a phrase. "Then you would not arrest a burglar, but watch him," he said, glancing keenly at Sage.
"The cases are entirely different, sir," was the reply; "a burglar invariably works on his own, a spy is more frequently than not a cog of a machine and must be replaced. He seldom works entirely alone."
"Go on," Mr. Llewellyn John had said, seeing that Sage paused and was intently regarding his finger-nails of his right hand.
"Even when burglars work in gangs, there is no superior organisation to replace destroyed units," continued Sage. "With international secret service it is different; its casualties are made good as promptly as with a field army."
"I believe you're right," said Mr. Llewellyn John. "If you can convince Colonel Walton, then Department Z. can be run on those lines."
Malcolm Sage had found no difficulty in convincing his chief, a man of quiet demeanour, but unprejudiced mind. The result had been that Department Z. had not so far caused a single arrest, although it had countered many clever schemes. Its motto was "The Day" when it could make a really historical haul.
The progress of Malcolm Sage had been remarkable. Colonel Walton had quickly seen that his subordinate could work only along his own lines, and in consequence he had given him his head. Sage, on his part, had discovered in his chief a man with a sound knowledge of human nature, generously spiced with the devil.
As Sage entered, Colonel Walton ceased his diagrams and looked up. Sage was as unlike the "sleuth hound" of fiction as it is possible for a man to be. At first glance he looked like the superintendent of a provincial Sunday-school. He was about thirty-five years of age, sandy, wore gold-rimmed glasses and possessed a conical head, prematurely bald. He had a sharp nose, steel-coloured eyes and large ears; but there was the set of his jaw which told of determination.
Seating himself in his customary place, Sage proceeded to pull at the inevitable briar, without which he was seldom seen. For a full minute there was silence. Colonel Walton deliberately lighted a cigar and leaned back to listen. He knew his man and refrained from asking questions.
"They're puzzled, chief" – Sage knocked the ashes from his pipe into the ash-tray on the table – "and they're getting jumpy," he added.
Colonel Walton nodded.
"Twice they've ransacked John Dene's room at the Ritzton and found nothing."
"Does he know?" enquired Colonel Walton.
Sage nodded.
"John Dene's a dark horse," he remarked with respect in his voice, "and the Huns can't make up their minds."
"To what?" enquired the chief.
"To give up the shadow for the substance," he remarked, as he pressed down the tobacco in his pipe. "They want the plans, and they want to prevent the boat from putting to sea."
Colonel Walton nodded comprehendingly.
"They'll probably try to scotch her on the way over; but they won't know her route. They'll be lying in wait, however, in full strength in home waters. He's a bad psychologist," added Sage, as he knocked the ashes out of his pipe.
"Who?" enquired Colonel Walton.
"The Hun," replied Sage, as he sucked away contentedly at his pipe. "He's never content to go for a single issue, or he'd probably have got the Channel ports. He's not content with concentrating on John Dene and his boat, he's after the plans. That's where he'll fail. Smart chap, John Dene."
For some moments the two men smoked in silence, which was finally broken by Sage.
"They'll try to get hold of John Dene, unless he's very careful, and hold him to ransom, the price being the plans."
"Incidentally, Sage, where did you get all this from?" enquired Walton.
Sage gazed at his chief through his gold-rimmed spectacles. "About three hundred yards west of the Temple Station on the Underground."
Colonel Walton glanced across at his subordinate; but refrained from asking further questions. "Have you warned Dene?" he enquired instead.
"No use," replied Sage with conviction. "Might as well warn a fly."
Colonel Walton nodded understandingly. "Still," he remarked, "I think he ought to be told."
"Why not have a try yourself?" Sage looked up swiftly from the inevitable contemplation of his finger-nails.
For fully a minute Colonel Walton sat revolving the proposal in his mind. "I think I will," he said later.
"He'll treat you like a superannuated policeman," was the grim retort.
"The Skipper wants to see us at eleven," said Colonel Walton, looking at his watch and rising. The "Skipper" was the name by which Mr. Llewellyn John was known at Department Z. Names were rarely referred to, and very few documents were ever exchanged. Colonel Walton picked up his hat from a bookcase and, followed by Sage, who extracted a cap from his pocket, left the room and Department Z. and walked across to Downing Street.
As Colonel Walton and Malcolm Sage were shown into Mr. Llewellyn John's room, the Prime Minister gave instructions that he was not to be disturbed for a quarter of an hour.
"Was the John Dene Report what you wanted, sir?" enquired Colonel Walton, as he took the seat Mr. Llewellyn John indicated.
"Excellent," cried Mr. Llewellyn John; then with a smile he added, "I was able to tell Sir Lyster quite a lot of things this morning. The Admiralty report was not ready until late last night. It was not nearly so instructive."
The main facts of John Dene's career had not been difficult to obtain. His father had emigrated to Canada in the early eighties; but, possessing only the qualifications of a clerk, he had achieved neither fame nor fortune. He had died when John Dene was eight years old, and his wife had followed him within eighteen months. After a varied career John Dene had drifted to the States, where as a youth he had entered a large engineering firm, and was instantly singled out as an inventor in embryo.
Several fortunate speculations had formed the foundation of a small fortune of twenty thousand dollars, with which he returned to Toronto. From that point his career had been one continual progression of successes. Everything he touched seemed to turn to gold, until "John's luck" became a well-known phrase in financial circles.
Unlike most successful business-men, he devoted a large portion of his time to his hobby, electrical engineering, and when the war broke out he sought to turn this to practical and patriotic uses.
"And when may we expect Mr. Dene's new submarine over?" enquired Malcolm Sage casually.
"Mr. Dene's new submarine!" Mr. Llewellyn John's hands dropped to his sides as he gazed at Sage in blank amazement. "His new submarine," he repeated.
"Yes, sir."
"What on earth do you know about it?" demanded Mr. Llewellyn John, looking at Sage with a startled expression.
"John Dene has invented a submarine," proceeded the literal Sage, "with some novel features, including a searchlight that has overcome the opacity of water. The thing is lying on the St. Lawrence River just below Quebec. Yesterday he called to see Sir Lyster Grayne, who brought him here with Admiral Heyworth."
Mr. Llewellyn John gazed in bewilderment at Malcolm Sage, his eyes shifted to Colonel Walton and then back again to Sage.
"But," he began, "you're watching us, not the enemy. Did you know of this?" he turned to the chief of Department Z.
Colonel Walton shook his head. "I haven't seen Sage since you telephoned yesterday until a few minutes ago," he said.
"Where