“It was in my own writing,” answered the Russian.  “It was a confidential communication intended for the eye of my dearest friend, and for his eye only.  It was unfinished when I lost it.  I had been staying a few days at one of your English spas when I joined you in the train on the day of the accident.  The MS., as far as it went, had all been written before I left home; but I took it with me in my despatch-box, together with other private papers, although I knew that I could not add a single line to it while I should be from home.  I have wished a thousand times since that I had left it behind me.”

“I have heard of people to whom cryptography is a favourite study,” said the Captain; “people who pride themselves on their ability to master the most difficult cipher ever invented.  Let us hope that your MS. has not fallen into the hands of one of these clever individuals.”

Platzoff shrugged his shoulders.  “Let us hope so, indeed,” he said.  “But I will not believe in any such untoward event.  Too long a time has elapsed since the loss for me not to have heard something respecting the MS., had it been found by anyone who knew how to make use of it.  Besides, I would defy the most clever reader of cryptography to master my MS. without—­Ah, Bah! where’s the use of talking about it?  Should not you like some tobacco?  Daylight’s last tint has vanished, and there is a chill air sweeping down from the hills.”

As they left the window, Platzoff added:  “One of the most annoying features connected with my loss arises from the fact that all my labour will have to be gone through again—­and very tedious work it is.  I am now engaged on a second MS., which is, as nearly as I can make it, a copy of the first one; and it is a task which must be done by myself alone.  To have even one confidant would be to stultify the whole affair.  Another glass of claret, and then I will introduce you to my sanctum.”

The coloured man who had opened the door for Captain Ducie had been in and out of the dining-room several times.  He was evidently a favourite servant.  Platzoff had addressed him as Cleon, and Ducie had now a question or two to ask concerning him.

Cleon was a mulatto, tall, agile and strong.  Not bad-looking by any means, but carrying with him unmistakable traces of the negro blood in his veins.  His hair was that of a genuine African—­crisp and black, and was one mass of short curls; but except for a certain fulness of the lips his features were of the ordinary Caucasian type.  He wore no beard, but a thin, straight line of black moustache.  His complexion was yellow, but a different yellow from that of his master—­dusky, passionate, lava-like; suggestive of fiery depths below.  His eyes, too, glowed with a smothered fire that seemed as if it might blaze out at any moment, and there was in them an expression of snake-like treachery that made Captain Ducie shudder involuntarily, as though he had seen some loathsome reptile, the first time he looked steadily into their half-veiled depths.  One look into each other’s eyes was sufficient for both these men.