On the second evening of my vigil in Sterndale Road my watchfulness was rewarded by seeing a neat and familiar figure pass up the street and enter the little newsagent’s.

It needed no second glance to tell me that the visitor to the shop was the mysterious girl who called me on that memorable night, from the dispensary at Walworth—Miss Bristowe.

Fortunately she had not noticed my presence. Therefore I at once concealed myself up a side passage and waiting till she emerged with a letter in her hand—the one I had addressed to Purvis, I expect—I started to follow her. Every moment I feared lest she might look round and discover me, for in those back streets of Hammersmith there is not much traffic. But I was determined on this occasion to follow her to her home or to the hiding-place of Purvis.

Turning down Brook Green Road, she walked as far as the Hammersmith Station of the Underground Railway, where she bought a ticket for Notting Hill and entered the next train going west. On alighting she traversed hurriedly the Lancaster Road, for it had begun to rain and she was without an umbrella, and, turning at last into the Cornwall Road, ascended the front steps of one of the dark, smoke-blackened houses in that thoroughfare, not far from the corner of Portobello Road. She rang, the door was immediately opened by a servant, and she disappeared within.

Then, after a brief wait, I passed the house near enough to note that its number was 120. She went in at half-past seven, and, although I waited in the rain until half an hour before midnight, she did not come forth again. I therefore concluded that I had at last gained knowledge of her place of abode.

I wondered whether Purvis lived in that same house. She had called for his letters at Sterndale Road, and would probably hand them to him at once. Therefore, after long reflection, I came to the conclusion that he must live at that address.

It was past one when I re-entered my own rooms, and for an hour before turning in, occupied myself in re-arranging the chaos effected by the unknown intruders. The latter had certainly been disappointed with the result of their investigation, for they had not troubled themselves about two of the valuable old manuscripts I had found on board the Seahorse—the Decretales Summa of the Monk Henry and the Book of John Trethemius—both of which were lying upon the mantelshelf. No, it was the key of the cipher of which they had been in such active search, but which was fortunately far beyond their reach.

Early next morning I renewed my vigil at the corner of the Portobello and Cornwall Roads, hoping to meet the pretty woman who had so charmed me.

Two hours I waited, until at last she emerged, as usual neatly dressed in black. Through the maze of complicated streets she walked to Westbourne Grove. She had made some purchases, and was gazing into one of Whiteley’s shop windows when I came up beside her and, raising my hat, greeted her.

She turned quickly, open-mouthed, and then, recovering from her surprise, at once gave me her hand and greeted me quite light-heartedly.

“Really, doctor,” she laughed, “you seem quite ubiquitous. You are always running up against me.”

“Well, it’s a doctor’s profession to go hither and thither quickly,” I answered. “How is your brother?”

“Greatly better,” was her prompt reply, although I thought I could detect duplicity in her answer. But she swiftly sought to change the subject, and as I walked beside her she chatted quite merrily. I did not, of course, let her know that I was aware of her abode, but, on the contrary, spoke of it as though it were away at Blackheath, and she did not seek to contradict me. Miss Bristowe was a clever woman in every sense of the word, but at the same time she was sweet and winning—most charming.

In her chatter was a light, irresponsible air that gave to her a chic seldom found in an Englishwoman, while her small hands and feet, her narrow waist, wide swinging hips, and the manner of her coiffure all savoured of the Parisienne rather than of the Londoner.

My object was to learn from her something definite regarding the man Purvis and his movements; her object was to conceal everything and to mislead me.

She seemed, however, nothing loth to allow me to accompany her into the several shops where she made small purchases. Once I referred to our meeting in Calthorpe Street, recollecting how cleverly Purvis had escaped me there, but she only laughed saying:?—

“You must have thought me very rude to hurry away as I did, but I wanted to get home.”

There were many matters I wished she would explain, but how could I ask her point-blank? For what reason had she taken me to Blackheath that night on a fruitless errand, and what connexion had she with the mysterious Purvis?

Again, it occurred to me that if Reilly had watched that newsagent’s in Sterndale Road he had probably met her. He might even have become acquainted with her for aught I knew. I had, I remembered, given him a detailed description.

But if they were acquainted, she would be utterly unaware of the young man’s association with me; hence I dare not broach the subject.

While I lingered at her side I could not help remarking, within myself, upon her affable courtesy and modest reserve towards me. A mystery surrounded her; that was certain. But in that half-hour I spent with her in Westbourne Grove I felt that she was not an adventuress, as I had half believed her to be, and that, save for the fact that she scrupulously concealed her place of abode, she was open and honest-minded, with a pleasing grace and sweet smile.

Again, just as I had noticed on the first occasion we had met, I detected that concealed within her heart was some deep-rooted sorrow, some painful memory of the past, perhaps, that she could not forget, and that now and then the sympathetic chord was struck that ............