Another regretted the writer’s inability to keep an appointment, as he had been called unexpectedly to Paris, and was compelled to leave by the night mail from Charing Cross. He, however, promised to return in three days, and gave her the Grand Hotel as his address if she found it necessary to telegraph.

Strangely enough, the letters contained no endearing terms either at their commencement or conclusion. Formal and brief, they all related to appointments at various places in London where two persons might meet unnoticed by the crowd, and all were signed by the single mysterious initial. I stood with them in my hand for a long time, puzzled and hesitating, then placing them carefully in my pocket, together with the secret document I had so unexpectedly unearthed, I crammed on my hat and hastily drove to Pont Street.

The house was in darkness, save for a light in the basement, and in answer to my summons, after a lapse of some minutes a tall, gaunt, woman in rusty black appeared in the area below.

I was surprised at being thus met by a stranger, but inquired for Mrs Laing.

“Mrs Laing ain’t at ’ome, sir,” answered the woman, looking up and speaking with a strong Cockney twang.

“Not at home?” I exclaimed, surprised. “Where is she?”

“She’s gone abroad somewheres, but I don’t know where,” the woman answered. “She’s sold all her valuables, discharged the servants, and left me ’ere as ’ouse-keeper.”

“When did she go?” I asked.

“This morning. I answered an advertisement in the Chronicle yesterday, and entered on my duties ’ere to-day. Quick, ain’t it?”

The rapidity of her engagement I was compelled to admit, but proceeded to make further inquiry whether Mrs Laing’s daughter had been there.