CHAPTER XXIX.
THE THEORY OF LING CHU Upon this scene came Ling Chu, imperturbable, expressionless, bringing with him his own atmosphere of mystery.
"Well," said Tarling, "what have you discovered ?" and even Whiteside checked his enthusiasm to listen.
"Two people came up the stairs last night," said Ling Chu, "also the master." He looked at Tarling, and the latter nodded.

"Your feet are clear," he said; "also the feet of the small-piece woman; also the naked feet." "The naked feet ?" said Tarling, and Ling Chu assented.
"What was the naked foot--man or woman ?" asked Whiteside.
"It may have been man or woman," replied the Chinaman, "but the feet were cut and were bleeding.

There is mark of blood on the gravel outside." "Nonsense!" said Whiteside sharply.
"Let him go on," warned Tarling.
"A woman came in and went out----" continued Ling Chu.
"That was Miss Rider," said Tarling.
"Then a woman and a man came; then the bare-footed one came, because the blood is over the first women's footmarks." "How do you know which was the first woman and which was the second ?" asked Whiteside, interested in spite of himself.
"The first woman's foot was wet," said Ling Chu.
"But there had been no rain," said the detective in triumph.
"She was standing on the grass," said Ling Chu, and Tarling nodded his head, remembering that the girl had stood on the grass in the shadow of the bushes, watching his adventure with Milburgh.
"But there is one thing I do not understand master," said Ling Chu.
"There is the mark of another woman's foot which I cannot find on the stair in the hall.

This woman walked all round the house; I think she walked round twice; and then she walked into the garden and through the trees." Tarling stared at him.
"Miss Rider came straight from the house on to the road," he said, "and into Hertford after me." "There is the mark of a woman who has walked round the house," insisted Ling Chu, "and, therefore, I think it was a woman whose feet were bare." "Are there any marks of a man beside us three ?" "I was coming to that," said Ling Chu.

"There is a very faint trace of a man who came early, because the wet footsteps are over his; also he left, but there is no sign of him on the gravel, only the mark of a wheel-track." "That was Milburgh," said Tarling.
"If a foot has not touched the ground," explained Ling Chu, "it would leave little trace.