But to the experienced eye there is a marked hiatus between half-past nine and eleven o’clock. At such a time Charing Cross is negotiable, Piccadilly Circus loses much of its terror, and a hansom may turn out of Regent Street into Oxford Street without the fare being impelled to clutch convulsively at the brass window-slide in a make-believe effort to save the vehicle from being crushed like a walnut shell between two heavy ’buses.

Such considerations did not appeal to the barrister and his companion on this occasion.

For some inexplicable cause they both felt that they were in a desperate hurry.

A momentary stoppage at the turn into Orchard Street caused each man to swear, quite unconsciously. Now that the supreme moment in this most painful investigation was at hand they resented the slightest delay. Though they were barely fifteen minutes in the cab, it seemed an hour before they alighted at Wensley House, Portman Square.

In response to an imperative ring a footman appeared. Instead of answering the barrister’s question as to whether Sir Charles was at home or not, he said: “You are Mr. Bruce, sir, aren’t you?”

“Yes.”

“Sir Charles is at home, but he retired to his room before dinner. He is not well, and he may have gone to bed, but he said that if you came you were to be admitted. I will ask Mr. Thompson.”

“Better send Thompson to me,” said Bruce decisively; and in a minute the old butler stood before him.

“I hear that Sir Charles has retired for the night,” said Claude.