Cary tried to shake my resolution, but I was obdurately silent. While he canvassed the whole position, bringing to bear his really profound knowledge of naval equipment and routine—and incidentally helping me greatly to realise the improbability of my own guesswork solution—I was able to maintain an air of lofty superiority. I must have aggravated him intensely, unpardonably, for I was his guest. He ought to have kicked me out. Yet he bore with me like the sweet-blooded kindly angel that he is, and when at the end it appeared that I was right after all, Cary was the first to pour congratulations and honest admiration upon me. If he reads this book he will know that I am repentant—though I must confess that I should behave in just the same abominable way if the incident were to occur again. There is no great value in repentance such as this.

We reached Dawson's office in the early afternoon, and found his chief assistant there, but no Dawson. "The old man," remarked that officer, a typical, stolid, faithful detective sergeant, "is out on the rampage. He ought by rights to sit here directing the staff and leave the outside investigations to me. He is a high-up man, almost a deputy assistant commissioner, and has no call to be always disguising himself and playing his tricks on everybody. I suppose you know that white-haired old gent down here ain't a bit like Bill Dawson, who's not a day over forty?"

"I have given up wondering where the real Dawson ends and where the disguises begin. The man I met up north wasn't the least bit like the one down here."

"A deal younger, I expect," said the chief assistant, grinning. "He shifts about between thirty and sixty. The old man is no end of a cure, and tries to take us in the same as he does you. There's an inspector at the Yard who was at school with him down Hampshire way, and ought to know what he is really like, but even he has given Dawson up. He says that the old man does not know his own self in the looking-glass; and as for Mrs. Dawson, I expect she has to take any one who comes along claiming to be her husband, for she can't, possibly tell t'other from which."

"One might make a good story out of that," I observed to Cary.

"I don't understand," said he. "Mr. Dawson told me once that I knew the real Dawson, but that few other people did."

"If he told you that," calmly observed the assistant, "you may bet your last shirt he was humbugging you. He couldn't tell the truth, not if he tried ever so."

"What is he at now?" I asked.

"I don't know, sir. And if he told me, I shouldn't believe him. I don't take no account of a word that man says. But he's the most successful detective we've got in the whole Force. He's sure to be head of the C.I.D. one day, and then he will have to stay in his office and give us others a chance."

"I don't believe he will," I observed, laughing. "There will be a sham Dawson in the office and the genuine article will be out on the rampage. He is a man who couldn't sit still, not even if you tied him in his chair and sealed the knots."

We spent a pleasant hour pulling Dawson to pieces and leaving to him not a rag of virtue, except intense professional zeal. We exchanged experiences of him, those of the chief assistant being particularly rich and highly flavoured. It appeared that Dawson when off duty loved to occupy the platform at meetings of his religious connection and to hold forth to the elect. The privilege of "sitting under him" had been enjoyed more than once by the assistant, who retailed to us extracts from Dawson's favourite sermon on "Truth." His views upon Truth were unbending as armour plate. "Under no circumstances, not to save oneself from imminent death, not to shield a wife or a child from the penalties for a lapse from virtue, not even to preserve one's country from the attacks of an enemy, was it permissible to a Peculiar Baptist to diverge by the breadth of a hair from the straight path of Truth. Hell yawned on either hand; only along the knife edge of Truth could salvation be reached."

"He made me shiver," said the chief assistant, "and he drove me to thinking of one or two little deceptions of my own. When Dawson preaches, his eyes blaze, his voice breaks, and he will fall on his knees and pray for the souls of those who heed not his words. You can't look at him then and not believe that he means every word he says. Yet it's all humbug."

"No, it is not," said I. "Dawson in the pulpit, or on the tub—or whatever platform he uses—is absolutely genuine. He is the finest example that I have ever met of the dual personality. He is in dead earnest when he preaches on Truth, and he is in just as dead earnest when, stripped of every moral scruple, he pursues a spy or a criminal. In pursuit he is ruthless as a Prussian, but towards the captured victim he can be strangely tender. I should not be surprised to learn that he hates capital punishment and is a strong advocate of gentle methods in prison discipline."

The chief assistant stared, opened a drawer, and pulled forth a slim grey pamphlet. It was marked "For Office Use Only," and was entitled, "Some Notes on Prison Reform," by Chief Inspector William Dawson.

I had begun to read the pamphlet, when a step sounded outside; the assistant snatched it from my hand, flashed it back into its place, and jumped to attention as Dawson entered. He surveyed us with those searching, unwinking eyes of his—for we had the air of conspirators—and said brusquely: "Clear out, Wilson. You talk too much. And don't admit any one except Petty Officer Trehayne."

"The Antigone!" cried Cary, who thought only of ships. "The Antigone! Is she much damaged?"

"No. Whoever tried to cut her wires was disturbed, or in too great a hurry to do his work well. The main gun-cable was nipped, but not cut through. She will be delayed till to-morrow, not longer. I am not worrying about the Antigone, but about the new battleship Malplaquet, which was commissioned last month, is nearly filled up with stores, and is expected to leave the river on Saturday. We can't have her delayed by any hanky tricks, not even if we have to put the whole detective force on board of her. Still, I'm not so anxious as I was. This Antigone business has cleared things up a lot, and one can sift out the impossible from the possible. To begin with, the Antinous was in for repairs to her geared turbines, and the Antigone for damage to her forefoot. Engineers were on one job, and platers and riveters on the other. Different trades. So not a workman who was in the Antinous was also in the Antigone. We can rule out all the workmen. We can also rule out my lieutenant R.N.R. with the German name who has gone to sea in the Antinous. The care and maintenance party in the Antigone was not the same as the one in the Antinous, not a man the same."

"You are sure of that?" cried I, for it seemed that my daring theory had gone to wreck. "You are quite sure."

"Quite. I have all the names and have examined all the men. They were all off the ship by eleven o'clock last night. I hadn't one of my own men among them, but, to make sure, I sent Petty Officer Trehayne on board at eight o'clock to keep a sharp look-out and to see all the harbour party off the vessel. He reported a little after eleven that they were all gone and the ship taken over by her own crew. The damage was discovered at four bells in the morning watch."

"Six o'clock a.m.," interpreted Cary.

"It looks now as if there might be a traitor among her own crew, which is her officers' job, not mine. I wash my hands of the Antigone, but it is very much up to me to see that nothing hurtful happens to the Malplaquet. The Admiral has orders to support me with all the force under his command; the General of the District has the same orders. But it isn't force we want so much as brains—Dawson's brains. I have been beaten twice, but not the third time. I've told the Yard that if the Malplaquet is touched I shall resign, and if they send any one to help me I shall resign. Between to-day, Thursday, and Saturday I am going to catch the wily josser who has a fancy for cutting gun cables or Dawson will say good-bye to the Force. That's a fair stake."

The man swelled with determination and pride. He had no thought of failure, and drew inspiration and joy from the heaviness of the bet which he had made with Fortune. He took the born gambler's delight in a big risk.

"Then you think that the Antinous and the Antigone were both damaged by the same man, and that he may have designs upon the Malplaquet?" said I.

"I don't propose to tell you what I think," replied Dawson stiffly.

"Still," I persisted, passing over the snub, "you have a theory?"

"No, thanks," said Dawson contemptuously. "I have no use for theories. When they are wrong they mislead you, and when they are right they are no help. I believe in facts—facts brought out by constant vigilance. Unsleeping watchfulness and universal suspicion, those are the principles I work on. The theory business makes pretty story books, but the Force does not waste good time over them."

"What are you going to do?"

"This is Thursday afternoon. I am going to join the Malplaquet presently, and I'm not going to sleep till she is safely down the river. I'm going to be my own watchman this time."

"How? In what capacity?"

Dawson gave a shrug of impatience, for his nerves were on edge. For a moment he hesitated, and then, recollecting the high post to which I had tacitly been appointed in his household, he replied:

"I am going as one of the Marine sentries."

"It's no use, Dawson," protested I emphatically. "You are a wonder at disguise, and will look, I do not doubt, the very spit of a Marine. But you can't pass among the men for half an hour without discovery. They are a class apart, they talk their own language, cherish their own secret traditions, live in a world to which no stranger ever penetrates. You could pass as a naval officer more easily than you could as a Pongo. It is sheer madness, Dawson."

He gave a short laugh. "Much you know about it. I have served in the Red Corps myself. I was a recruit at Deal, passed two years at Plymouth, and served afloat for three years. I was then drafted into the Naval Police. Afterwards I was recommended for detective work in the dockyards, and at the end of my Marine service joined the Yard. My good man, I was a sergeant before I left the Corps."

"I give up, Dawson," said I. "Nothing about you will ever surprise me again. Not even if you claim to have been a Cabinet Minister."

A queer smile stole over his face. "No, I have not been a minister, but I have attended a meeting of the Cabinet."

Cary interposed at this point. "Yours is a fine idea, Mr. Dawson. As a Marine sentry you can get yourself posted by the Major wherever you please, and the Guard will not talk even though they may wonder that any man should want to do twenty-four hours of duty per day. The Marines are the closest, faith-fullest, and best disciplined force in the wide world. Bluejackets will gossip; Marines never. You will be able to watch more closely than even Trehayne, who, I suppose, will also be on board."

"Yes. He is coming up soon for instructions. It's his last chance, as it is mine. He sees that he must be held responsible for the wire cutting in the Antinous, and to some slight extent also in the Antigone, and that if anything goes wrong with the Malplaquet he will be dismissed. I shall be sorry to lose him, for he is an exceptionally good man, but we can't allow failures in petty officer detectives any more than we can in chief inspectors."

"Where does Trehayne come from? His name sounds Cornish," I asked.

"Falmouth, I believe. He is quite young, but he has had nearly three years in the Vernon at Portsmouth and in the torpedo factory at Greenock. A first-class engineer and electrician and a sound detective. He has been with me for some twelve months. You will see him if he calls soon."

I had been thinking hard over the details of Dawson's plans while the talk went on, and then ventured to offer some comments.

"It is fortunate that you have grown a moustache since you were in the north; you could not have been a Marine as a clean-shaven man."

"I often have to shave it," said Dawson, "but I always grow it again between whiles. One can take it off quicker than one can put it on again. False hair is the devil; I have never used it yet and never will. So whenever I have a spell of leisure I grow a moustache against emergencies—like this one."

My next comment was rather difficult to make, for I did not wish either Cary or Dawson to divine its purpose. "If I may make a suggestion to a man of your experience it would be that none of your men here, not even your chief assistant or Trehayne, should know that you are joining the Malplaquet as a Marine. Two independent strings are in this case better than a double-jointed string."

"I never tell anything to any one, least of all to Pudden-Headed Wilson. He is loyal, but a stupid ass with a flapping tongue. Trehayne is close as wax, but, on general principles, I keep my movements strictly to myself. He will be in the ship, but he won't know that I am there too. The Commander must know and the Major of Marines, for I shall want a uniform and the free run of the ship, so as to be posted where I like. The Marine Sergeants of the Guard may guess, but, as Mr. Cary says, they won't talk. You two gentlemen are safe," added Dawson pleasantly, "for I've got you tight in my hand and could lock either of you up in a minute if I chose."

A peculiar knock came upon the door, a word passed between Dawson and the police sentry outside, and a young man in the uniform of a naval petty officer entered the room. He was clean-shaven, looked about twenty-five years old, was dark and slim of the Latin type which is not uncommon in Cornwall, and impressed me at once with his air of intelligence and refinement. His voice, too, was rather striking. It was that of the wardroom rather than of the mess deck. I liked the look of Petty Officer Trehayne. Dawson presented him to us and then took him aside for instructions. When he had finished, both men rejoined us, and the conversation became light and general. Trehayne, though clearly suffering from nervous strain after his recent professional failures, talked with the ease and detachment of a highly cultivated man. It appeared that he had been educated at Blundell's School, had lost his parents at about sixteen, had done a course in some electrical engineering shops at Plymouth, and when twenty years old had secured a good berth on the engineering staff of the Vernon. He could speak both French and German, which he had learned partly at school and partly on the Continent during leave. Dawson, who was evidently very proud of his young pupil and assistant, paraded his accomplishments before us rather to Trehayne's embarrassment. "Try him with French and German," urged Dawson. "He can chatter them as well as English. But he is as close as wax in all three languages. Some men can't keep their tongues still in one."

I turned to Trehayne and spoke in French: "German I can't abide, but French I love. My vocabulary is extensive, but my accent abominable—incurably British. You can hear it for yourself how it gives me away."

"It is not quite of Paris," replied Trehayne. "Mais vous parlez francais tres bien, tres correctement. Beaucoup mieux que moi."

"Non, non, monsieur," I protested, and then reverted to English.

"Now," said Dawson, when Trehayne had left us, "I must get along, see the Commander of the Malplaquet, and draw a uniform and rifle out of the marine stores. It will be quite like old times. You won't see me until Saturday, when I shall be either a triumphant or a broken man. What is the betting, Mr. Copplestone?"

I could not understand the quizzical little smile that Dawson gave me, nor the humorous twitch of his lips. He had contemptuously disclaimed all use of theories, yet there was more moving behind that big forehead of his than he chose to give away. Did his ideas run on parallel lines with mine; did he even suspect that I had formed any idea at all? I could not inquire, for I dislike being laughed at, especially by this man Dawson. I had nothing to go upon, at least so little that was palpable that anything which I might say would be dismissed as the merest guesswork, for which, as Dawson proclaimed, he had no use. Yet, yet—my original guess stuck firmly in my mind, improbable though it might be, and had just been nailed down tightly—I scorn to mystify the reader—by a few simple sentences spoken in French.