Seeing where the head of the monster was, the two men ventured a little further forward, and saw that the hidden mass at the base of the shaft was composed of vast coils of the great serpent’s body, forming a base from which the upright mass rose.  As they looked, this lower mass moved, the glistening folds catching the moonlight, and they could see that the monster’s progress was along the ground.  It was coming towards them at a swift pace, so they turned and ran, taking care to make as little noise as possible, either by their footfalls or by disturbing the undergrowth close to them.  They did not stop or pause till they saw before them the high dark tower of Doom.

CHAPTER XXIII—­IN THE ENEMY’S HOUSE

Sir Nathaniel was in the library next morning, after breakfast, when Adam came to him carrying a letter.

“Her ladyship doesn’t lose any time.  She has begun work already!”

Sir Nathaniel, who was writing at a table near the window, looked up.

“What is it?” said he.

Adam held out the letter he was carrying.  It was in a blazoned envelope.

“Ha!” said Sir Nathaniel, “from the White Worm!  I expected something of the kind.”

“But,” said Adam, “how could she have known we were here?  She didn’t know last night.”

“I don’t think we need trouble about that, Adam.  There is so much we do not understand.  This is only another mystery.  Suffice it that she does know—­perhaps it is all the better and safer for us.”

“How is that?” asked Adam with a puzzled look.

“General process of reasoning, my boy; and the experience of some years in the diplomatic world.  This creature is a monster without heart or consideration for anything or anyone.  She is not nearly so dangerous in the open as when she has the dark to protect her.  Besides, we know, by our own experience of her movements, that for some reason she shuns publicity.  In spite of her vast bulk and abnormal strength, she is afraid to attack openly.  After all, she is only a snake and with a snake’s nature, which is to keep low and squirm, and proceed by stealth and cunning.  She will never attack when she can run away, although she knows well that running away would probably be fatal to her.  What is the letter about?”

Sir Nathaniel’s voice was calm and self-possessed.  When he was engaged in any struggle of wits he was all diplomatist.

“She asks Mimi and me to tea this afternoon at Diana’s Grove, and hopes that you also will favour her.”

Sir Nathaniel smiled.

“Please ask Mrs. Salton to accept for us all.”

“She means some deadly mischief.  Surely—­surely it would be wiser not.”

“It is an old trick that we learn early in diplomacy, Adam—­to fight on ground of your own choice.  It is true that she suggested the place on this occasion; but by accepting it we make it ours.  Moreover, she will not be able to understand our reason for doing so, and her own bad conscience—­if she has any, bad or good—­and her own fears and doubts will play our game for us.  No, my dear boy, let us accept, by all means.”