On the western side of the tower stood a grove of old trees, of forest dimensions.  They were not grouped closely, but stood a little apart from each other, producing the effect of a row widely planted.  Over the tops of them was seen a green light, something like the danger signal at a railway-crossing.  It seemed at first quite still; but presently, when Adam’s eye became accustomed to it, he could see that it moved as if trembling.  This at once recalled to Adam’s mind the light quivering above the well-hole in the darkness of that inner room at Diana’s Grove, Oolanga’s awful shriek, and the hideous black face, now grown grey with terror, disappearing into the impenetrable gloom of the mysterious orifice.  Instinctively he laid his hand on his revolver, and stood up ready to protect his wife.  Then, seeing that nothing happened, and that the light and all outside the tower remained the same, he softly pulled the curtain over the window.

Sir Nathaniel switched on the light again, and in its comforting glow they began to talk freely.

CHAPTER XXII—­AT CLOSE QUARTERS

“She has diabolical cunning,” said Sir Nathaniel.  “Ever since you left, she has ranged along the Brow and wherever you were accustomed to frequent.  I have not heard whence the knowledge of your movements came to her, nor have I been able to learn any data whereon to found an opinion.  She seems to have heard both of your marriage and your absence; but I gather, by inference, that she does not actually know where you and Mimi are, or of your return.  So soon as the dusk fails, she goes out on her rounds, and before dawn covers the whole ground round the Brow, and away up into the heart of the Peak.  The White Worm, in her own proper shape, certainly has great facilities for the business on which she is now engaged.  She can look into windows of any ordinary kind.  Happily, this house is beyond her reach, if she wishes—­as she manifestly does—­to remain unrecognised.  But, even at this height, it is wise to show no lights, lest she might learn something of our presence or absence.”

“Would it not be well, sir, if one of us could see this monster in her real shape at close quarters?  I am willing to run the risk—­for I take it there would be no slight risk in the doing.  I don’t suppose anyone of our time has seen her close and lived to tell the tale.”

Sir Nathaniel held up an expostulatory hand.

“Good God, lad, what are you suggesting?  Think of your wife, and all that is at stake.”

“It is of Mimi that I think—­for her sake that I am willing to risk whatever is to be risked.”

Adam’s young bride was proud of her man, but she blanched at the thought of the ghastly White Worm.  Adam saw this and at once reassured her.

“So long as her ladyship does not know whereabout I am, I shall have as much safety as remains to us; bear in mind, my darling, that we cannot be too careful.”