Was it possible that her ears had deceived her?  Was it one of the omens believed in by the superstitious?  The wall whence the voices appeared to emanate was, she knew, about seven feet thick—­an outer wall of the old keep.  She was aware of this because in one of the folio tomes in the library was a picture of the castle as it appeared in 1510, taken from some manuscript of that period preserved in the British Museum.  She, who had explored the ruins dozens of times, knew well that at the point where she was standing there could be no place of concealment.  Beyond that wall, the hill, covered with bushes and brushwood, descended sheer for three hundred feet or so to the bottom of the glen.  Had the voices sounded from one or other of the half-choked chambers which remained more or less intact she would not have been so puzzled; but, as it was, the weird whisperings seemed to come forth from space.  Sometimes they sounded so low that she could scarcely hear them; at others they were so loud that she could almost distinguish the words uttered by the unseen.  Was it merely a phenomenon caused by the wind blowing through some crack in the ponderous lichen-covered wall?

She looked beyond at the great dark yew, the justice-tree of the Grahams.  The night was perfectly calm.  Not a leaf stirred either upon that or upon the other trees.  The ivy, high above and exposed to the slightest breath of a breeze, was motionless; only the going and coming of the night-birds moved it.  No.  She decided once and for all that the noise was that of voices, spectral voices though they might be.

Again she strained her eyes, when still again those soft, sibilant whisperings sounded weird and quite inexplicable.

Slowly, and with greatest caution, she moved along beneath the wall, but as she did so she seemed to recede from the sound.  So back she went to the spot where she had previously stood, and there again remained listening.

There were two distinct voices; at least that was the conclusion at which she arrived after nearly a quarter of an hour of most minute investigation.

Once she fancied, in her excitement, that away in the farther corner of the ruined courtyard she saw a slowly moving form like a thin column of mist.  Was it the Lady of Glencardine—­the apparition of the hapless Lady Jane Glencardine?  But on closer inspection she decided that it was merely due to her own distorted imagination, and dismissed it from her mind.

Those low, curious whisperings alone puzzled her.  They were certainly not sounds that could be made by any rodents within the walls, because they were voices, distinctly and indisputably voices, which at some moments were raised in argument, and then fell away into sounds of indistinct murmuring.  Whence did they come?  She again moved noiselessly from place to place, at length deciding that only at one point—­the point where she had first stood—­could the sounds be heard distinctly.