orning of the
earth; a man of the stone age--a man of stone.

One hope remained, the summoning of the household; and Father Brown ran
back into the house. He found, however, that all the under servants
had been given a holiday ashore by the autocrat Paul, and that only the
sombre Mrs. Anthony moved uneasily about the long rooms. But the moment
she turned a ghastly face upon him, he resolved one of the riddles of
the house of mirrors. The heavy brown eyes of Antonelli were the heavy
brown eyes of Mrs. Anthony; and in a flash he saw half the story.

"Your son is outside," he said without wasting words; "either he or the
prince will be killed. Where is Mr. Paul?"

"He is at the landing-stage," said the woman faintly. "He is--he
is--signalling for help."

"Mrs. Anthony," said Father Brown seriously, "there is no time for
nonsense. My friend has his boat down the river fishing. Your son's boat
is guarded by your son's men. There is only this one canoe; what is Mr.
Paul doing with it?"

"Santa Maria! I do not know," she said; and swooned all her length on
the matted floor.

Father Brown lifted her to a sofa, flung a pot of water over her,
shouted for help, and then rushed down to the landing-stage of the
little island. But the canoe was already in mid-stream, and old Paul
was pulling and pushing it up the river with an energy incredible at his
years.

"I will save my master," he cried, his eyes blazing maniacally. "I will
save him yet!"

Father Brown could do nothing but gaze after the boat as it struggled
up-stream and pray that the old man might waken the little town in time.

"A duel is bad enough," he muttered, rubbing up his rough dust-coloured
hair, "but there's something wrong about this duel, even as a duel. I
feel it in my bones. But what can it be?"

As he stood staring at the water, a wavering mirror of sunset, he
heard from the other end of the island garden a small but unmistakable
sound--the cold concussion of steel. He turned his head.

Away on the farthest cape or headland of the long islet, on a strip of
turf beyond the last rank of roses, the duellists had already crossed
swords. Evening above them was a dome of virgin gold, and, distant as
they were, every detail was picked out. They had cast off their coats,
but the yellow waistcoat and white hair of Saradine, the red waistcoat
and white trousers of Antonelli, glittered in the level light like the
colours of the dancing clockwork dolls. The t