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 on his nerves; "will you tell me this story or not? What other evidence is there to go on?"
"There are three more bits of evidence," said the other, "that I have dug up in holes and corners; and I will give them in logical rather than chronological order. First of all, of course, our authority for the issue and event of the battle is in Olivier's own dispatches, which are lucid enough. He was entrenched with two or three regiments on the heights that swept down to the Black River, on the other side of which was lower and more marshy ground. Beyond this again was gently rising country, on which was the first English outpost, supported by others which lay, however, considerably in its rear. The British forces as a whole were greatly superior in numbers; but this particular regiment was just far enough from its base to make Olivier consider the project of crossing the river to cut it off. By sunset, however, he had decided to retain his own position, which was a specially strong one. At daybreak next morning he was thunderstruck to see that this stray handful of English, entirely unsupported from their rear, had flung themselves across the river, half by a bridge to the right, and the other half by a ford higher up, and were massed upon the marshy bank below him.
"That they should attempt an attack with such numbers against such a position was incredible enough; but Olivier noticed something yet more extraordinary. For instead of attempting to seize more solid ground, this mad regiment, having put the river in its rear by one wild charge, did nothing more, but stuck there in the mire like flies in treacle. Needless to say, the Brazilians blew great gaps in them with artillery, which they could only return with spirited but lessening rifle fire. Yet they never broke; and Olivier's curt account ends with a strong tribute of admiration for the mystic valour of these imbeciles. 'Our line then advanced finally,' writes Olivier, 'and drove them into the river; we captured General St. Clare himself and several other officers. The colonel and the major had both fallen in the battle. I cannot resist saying that few finer sights can have been seen in history than the last stand of this extraordinary regiment; wounded officers picking up the rifles of dead soldiers, and the general himself facing us on horseback bareheaded and with a broken sword.' On what happened to the general afterwards Olivier is as silent as Captain Keith."
"Well," grunted Flambeau, "get on to the next bit of evidence."
"The next evidence," said Father Brown, "took some time to find, but it will not take long to tell. I found at last in an almshouse down in the Lincolnshire Fens an old soldier who not only was wounded at the Black River, but had actually knelt beside the colonel of the regiment when he died. This latter was a certain Colonel Clancy, a big bull of an Irishman; and it would seem that he died almost as much of rage as of bullets. He, at any rate, was not responsible for that ridiculous raid; it must have been imposed on him by the general. His last edifying words, according to my informant, were these: 'And there goes the damned old donkey with the end of his sword knocked off. I wish it was his head.' You will remark that everyone seems to have noticed this detail about the broken sword blade, though most people regard it somewhat more reverently than did the late Colonel Clancy. And now for the third fragment."
Their path through the woodland began to go upward, and the speaker paused a little for breath before he went on. Then he continued in the same business-like tone:
"Only a month or two ago a certain Brazilian official died in England, having quarrelled with Olivier and left his country. He was a well-known figure both here and on the Continent, a Spaniard named Espado; I knew him myself, a yellow-faced old dandy, with a hooked nose. For various private reasons I had permission to see the documents he had left; he was a Catholic, of course, and I had been with him towards the end. There was nothing of his that lit up any corner of the black St. Clare business, except five or six common exercise books filled with the diary of some English soldier. I can only suppose that it was found by the Brazilians on one of those that fell. Anyhow, it stopped abruptly the night before the battle.
"But the account of that last day in the poor fellow's life was certainly worth reading. I have it on me; but it's too dark to read it here, and I will give you a résumé. The first part of that entry is full of jokes, evidently flung about among the men, about somebody called the Vulture. It does not seem as if this person, whoever he was, was one of themselves, nor even an Englishman; neither is he exactly spoken of as one of the enemy. It sounds rather as if he were some local go-between and non-combatant; perhaps a guide or a journalist. He has been closeted with old Colonel Clancy; but is more often seen talking to the major. Indeed, the major is somewhat prominent in this soldier's narrative; a lean, dark-haired man, apparently, of the name of Murray—a north of Ireland man and a Puritan. There are continual jests about the contrast between this Ulsterman's austerity and the conviviality of Colonel Clancy. There is also some joke about the Vulture wearing bright-coloured clothes.
"But all these levities are scattered by what may well be called the note of a bugle. Behind the English camp and almost parallel to the river ran one of the few great roads of that district. Westward the road curved round towards
