large one, and was captured after heroic resistance. And it knows that after his capture, and to the abhorrence of the civilised world, St. Clare was hanged on the nearest tree. He was found swinging there after the Brazilians had retired, with his broken sword hung round his neck."
"And that popular story is untrue?" suggested Flambeau.
"No," said his friend quietly, "that story is quite true, so far as it goes."
"Well, I think it goes far enough!" said Flambeau; "but if the popular story is true, what is the mystery?"
They had passed many hundreds of grey and ghostly trees before the little priest answered. Then he bit his finger reflectively and said: "Why, the mystery is a mystery of psychology. Or, rather, it is a mystery of two psychologies. In that Brazilian business two of the most famous men of modern history acted flat against their characters. Mind you, Olivier and St. Clare were both heroes—the old thing, and no mistake; it was like the fight between Hector and Achilles. Now, what would you say to an affair in which Achilles was timid and Hector was treacherous?"
"Go on," said the large man impatiently as the other bit his finger again.
"Sir Arthur St. Clare was a soldier of the old religious type—the type that saved us during the Mutiny," continued Brown. "He was always more for duty than for dash; and with all his personal courage was decidedly a prudent commander, particularly indignant at any needless waste of soldiers. Yet in this last battle he attempted something that a baby could see was absurd. One need not be a strategist to see it was as wild as wind; just as one need not be a strategist to keep out of the way of a motor-bus. Well, that is the first mystery; what had become of the English general's head? The second riddle is, what had become of the Brazilian general's heart? President Olivier might be called a visionary or a nuisance; but even his enemies admitted that he was magnanimous to the point of knight errantry. Almost every other prisoner he had ever captured had been set free or even loaded with benefits. Men who had really wronged him came away touched by his simplicity and sweetness. Why the deuce should he diabolically revenge himself only once in his life; and that for the one particular blow that could not have hurt him? Well, there you have it. One of the wisest men in the world acted like an idiot for no reason. One of the best men in the world acted like a fiend for no reason. That's the long and the short of it; and I leave it to you, my boy."
"No, you don't," said the other with a snort. "I leave it to you; and you jolly well tell me all about it."
"Well," resumed Father Brown, "it's not fair to say that the public impression is just what I've said, without adding that two things have happened since. I can't say they threw a new light; for nobody can make sense of them. But they threw a new kind of darkness; they threw the darkness in new directions. The first was this. The family physician of the St. Clares quarrelled with that family, and began publishing a violent series of articles, in which he said that the late general was a religious maniac; but as far as the tale went, this seemed to mean little more than a religious man. Anyhow, the story fizzled out. Everyone knew, of course, that St. Clare had some of the eccentricities of puritan piety. The second incident was much more arresting. In the luckless and unsupported regiment which made that rash attempt at the Black River there was a certain Captain Keith, who was at that time engaged to St. Clare's daughter, and who afterwards married her. He was one of those who were captured by Olivier, and, like all the rest except the general, appears to have been bounteously treated and promptly set free. Some twenty years afterwards this man, then Lieutenant-Colonel Keith, published a sort of autobiography called 'A British Officer in Burmah and Brazil.' In the place where the reader looks eagerly for some account of the mystery of St. Clare's disaster may be found the following words: 'Everywhere else in this book I have narrated things exactly as they occurred, holding as I do the old-fashioned opinion that the glory of England is old enough to take care of itself. The exception I shall make is in this matter of the defeat by the Black River; and my reasons, though private, are honourable and compelling. I will, however, add this in justice to the memories of two distinguished men. General St. Clare has been accused of incapacity on this occasion; I can at least testify that this action, properly understood, was one of the most brilliant and sagacious of his life. President Olivier by similar report is charged with savage injustice. I think it due to the honour of an enemy to say that he acted on this occasion with even more than his characteristic good feeling. To put the matter popularly, I can assure my countrymen that St. Clare was by no means such a fool nor Olivier such a brute as he looked. This is all I have to say; nor shall any earthly consideration induce me to add a word to it.'"
A large frozen moon like a lustrous snowball began to show through the tangle of twigs in front of them, and by its light the narrator had been able to refresh his memory of Captain Keith's text from a scrap of printed paper. As he folded it up and put it back in his pocket Flambeau threw up his hand with a French gesture.
"Wait a bit, wait a bit," he cried excitedly. "I believe I can guess it at the first go."
He strode on, breathing hard, his black head and bull neck forward, like a man winning a walking race. The little priest, amused and interested, had some trouble in trotting beside him. Just before them the trees fell back a little to left and right, and the road swept downwards across a clear, moonlit valley, till it dived again like a rabbit into the wall of another wood. The entrance to the farther forest looked small and round, like the black hole of a remote railway tunnel. But it was within some hundred yards, and gaped like a cavern before Flambeau spoke again.
"I've got it," he cried at last, slapping his thigh with his great hand. "Four minutes' thinking, and I can tell your whole story myself."
"All right," assented his friend. "You tell it."
Flambeau lifted his head, but lowered his voice. "General Sir Arthur St. Clare," he said, "came of a family in which madness was hereditary; and his whole aim was to keep this from his daughter, and even, if possible, from his future son-in-law. Rightly or wrongly, he thought the final collapse was close, and resolved on suicide. Yet ordinary suicide would blazen the very idea he dreaded. As the campaign approached the clouds came thicker on his brain; and at last in a mad moment he sacrificed his public duty to his private. He rushed rashly into battle, hoping to fall by the first shot. When he found that he had only attained capture and discredit, the sealed bomb in his brain burst, and he broke his own sword and hanged himself."
He stared firmly at the grey façade of forest in front of him, with the one black gap in it, like the mouth of the grave, into which their path plunged. Perhaps something menacing in the road thus suddenly swallowed reinforced his vivid vision of the tragedy, for he shuddered.
"A horrid story," he said.
"A horrid story," repeated the priest with bent head. "But not the real story."
Then he threw back his head with a sort of despair and cried: "Oh, I wish it had been."
The tall Flambeau faced round and stared at him.
"Yours is a clean story," cried Father Brown, deeply moved. "A sweet, pure, honest story, as open and white as that moon. Madness and despair are innocent enough. There are worse things, Flambeau."
Flambeau looked up wildly at the moon thus invoked; and from where he stood one black tree-bough curved across it exactly like a devil's horn.
"Father—father," cried Flambeau with the French gesture and stepping yet more rapidly forward, "do you mean it was worse than that?"
"Worse than that," said Paul like a grave echo. And they plunged into the black cloister of the woodland, which ran by them in a dim tapestry of trunks, like one of the dark corridors in a dream.
They were soon in the most secret entrails of the wood, and felt close about them foliage that they could not see, when the priest said again:
"Where does a wise man hide a leaf? In the forest. But what does he do if there is no forest?"
"Well, well," cried Flambeau irritably, "what does he do?"
"He grows a forest to hide it in," said the priest in an obscure voice. "A fearful sin."
"Look here," cried his friend impatiently, for the dark wood and the dark saying got a little