"That's all, sir."

"Very good."

Sergeant Sowerby retired.

"Now, sir," said Dunbar, "I've got Inspector Kelly here. He looks after the Chinese quarter. Shall I call him?"

"Yes, Inspector."

Presently there entered a burly Irishman, bluff and good-humoured, a very typical example of the intelligent superior police officer, looking keenly around him.

"Ah, Inspector," the Assistant Commissioner greeted him—"we want your assistance in a little matter concerning the Chinese residential quarter. You know this district?"

"Certainly, sir. I know it very well."

"On this map"—the Assistant Commissioner laid a discoloured forefinger upon the map of London—"you will perceive that we have drawn a circle."

Inspector Kelly bent over the table.