"The four-wheeler?" repeated Frank. "The one driven by Henry which the red-haired man used as a blind, or the second owned by Bike in which I followed?"

"Neither. I am alluding to the third cab which was not on the stand when you returned at one o'clock."

"I don't see what that cab has to do with the business."

"Mr. Darrel! Mr. Darrel!" cried Torry gently. "You may be a good novelist, but, if you'll pardon my saying so, sir, you are a very bad detective. Is it not reasonable to suppose that the woman, anxious to get as far as possible from the scene of her crime would come up Mortality-lane and jump into the third cab? Also you must not forget that she had a rendezvous at Cleopatra's Needle, and, perhaps had to drive quickly to be in time."

"Yes; but coming into contact with a cabman she ran the risk of being--recognised. She must have known that when the murder was discovered the police would probably guess her flight in the four-wheeler, and inquire about her from the driver. He would give her description and----"

"Oh, that is very well!" said Torry, dismissing this objection with a wave of his plump hand, "but the woman never guessed for a moment that chance would intervene; and that by means of her death we should obtain evidence of her crime. She thought she would escape scot-free; also I daresay she was disguised. Or it might be that she was too agitated to pay attention to the risk she ran.

"Anyhow, I am certain that she used the third cab to get away; and I am going to look up the driver."

"How will you find him?"

"By questioning Henry and Bike. Moreover, he may be on the cab-stand himself. I tell you what. Mr. Darrel," cried Torry, getting on his short legs, "let us make a division of labour. You go to Harcot and Harcot in Bond-street to find out what is the name attached to the letters, 'J.G.,' and I'll see to the cabman."

"Very good, Mr. Torry. When and where am I to see you?"