On each of the floors below there had been a dim light—­a jet of gas turned low.  But the fifth floor was in darkness.  Someone had put out the light, either in carelessness or for some special reason.

There were several doors on each side of the passage, but I could not be sure that I had reached the right one until I’d lighted a match.  When I was sure, I knocked, but no answer came.

“He can’t be out,” I said to myself, cheerfully.  “He’s got tired of waiting and dropped asleep, that’s all.”

I knocked again.  Silence.  And then for a third time, loudly, keeping on until I was sure that, if there were anyone in the room, no matter how sound asleep, I must have waked him.

After all, he had gone out, but perhaps only for a short time.  Surely, he would soon come back, lest he should miss the keeper of the diamonds.

I had very little hope that, even on the chance of my arriving while he was away, he would have left the door open.  Nevertheless I tried the handle, and to my surprise it yielded.

“That must be because the lock’s broken and only a bolt remains,” I thought.  “So he had to take the risk.  All the better.  This looks as if he’d be back any minute.  He wouldn’t like giving the enemy a chance to find his lair and step into it before him.”  It was dark in the room, and I struck another wax match just inside the threshold.  But I had hardly time to get an impression of bareness and meanness of furnishing before a draught of air from an open window blew out the struggling flame and at the same instant banged the door shut behind me.

CHAPTER XIII

IVOR FINDS SOMETHING IN THE DARK

There was a strong smell of paraffin oil in the room; and from somewhere at the far end came a faint tap, tapping sound, which might be the light knocking of a window-blind or the rap of a signalling finger.

If I could steer my way to the window and pull back the drawn curtains I might be able to let in light enough to find matches on mantelpiece or table.  Then, what good luck if I should discover the case containing the treaty and go off with it before “J.M.” came back!  It was not his, and he was a thief:  therefore, I should be doing him no wrong and Maxine de Renzie much good by taking it, if he had left it behind, not too well hidden when he went out.

Guided in the darkness by a slight breeze which still came through the window, though the door was now shut, I shuffled across the uncarpeted floor, groping with hands held out before me as I moved.

In a moment I brushed against a table, then struck my shin on something which proved to be the leg of a chair lying over-turned on the floor.  I pushed it out of the way, but had gone on no more than three or four steps when I caught my foot in a rug which had got twisted in a heap round the fallen chair.  I disentangled myself from its coils, only to slip and almost lose my balance by stepping into some spilled liquid which lay thick and greasy on the bare boards.