The more Mimi thought over the late events, the more puzzled she was. What did it all mean--what could it mean, except that there was an error of fact somewhere. Could it be possible that some of them--all of them had been mistaken, that there had been no White Worm at all? On either side of her was a belief impossible of reception. Not to believe in what seemed apparent was to destroy the very foundations of belief. . . yet in old days there had been monsters on the earth, and certainly some people had believed in just such mysterious changes of identity. It was all very strange. Just fancy how any stranger--say a doctor--would regard her, if she were to tell him that she had been to a tea-party with an antediluvian monster, and that they had been waited on by up-to-date men-servants.

Adam had returned, exhilarated by his walk, and more settled in his mind than he had been for some time. Like Mimi, he had gone through the phase of doubt and inability to believe in the reality of things, though it had not affected him to the same extent. The idea, however, that his wife was suffering ill-effects from her terrible ordeal, braced him up. He remained with her for a time, then he sought Sir Nathaniel in order to talk over the matter with him. He knew that the calm common sense and self-reliance of the old man, as well as his experience, would be helpful to them all.

Sir Nathaniel had come to the conclusion that, for some reason which he did not understand, Lady Arabella had changed her plans, and, for the present at all events, was pacific. He was inclined to attribute her changed demeanour to the fact that her influence over Edgar Caswall was so far increased, as to justify a more fixed belief in his submission to her charms.

As a matter of fact, she had seen Caswall that morning when she visited Castra Regis, and they had had a long talk together, during which the possibility of their union had been discussed. Caswall, without being enthusiastic on the subject, had been courteous and attentive; as she had walked back to Diana's Grove, she almost congratulated herself on her new settlement in life. That the idea was becoming fixed in her mind, was shown by a letter which she wrote later in the day to Adam Salton, and sent to him by hand. It ran as follows:

"DEAR MR. SALTON,

"I wonder if you would kindly advise, and, if possible, help me in a matter of business. I have been for some time trying to make up my mind to sell Diana's Grove, I have put off and put off the doing of it till now. The place is my own property, and no one has to be consulted with regard to what I may wish to do about it. It was bought by my late husband, Captain Adolphus Ranger March, who had another residence, The Crest, Appleby. He acquired all rights of all kinds, including mining and sporting. When he died, he left his whole property to me. I shall feel leaving this place, which has become endeared to me by many sacred memories and affections--the recollection of many happy days of my young married life, and the more than happy memories of the man I loved and who loved me so much. I should be willing to sell the place for any fair price--so long, of course, as the purchaser was one I liked and of whom I approved. May I say that you yourself would be the ideal person. But I dare not hope for so much. It strikes me, however, that among your Australian friends may be someone who wishes to make a settlement in the Old Country, and would care to fix the spot in one of the most historic regions in England, full of romance and legend, and with a never-ending vista of historical interest--an estate which, though small, is in perfect condition and with illimitable possibilities of development, and many doubtful--or unsettled-- rights which have existed before the time of the Romans or even Celts, who were the original possessors. In addition, the house has been kept up to the DERNIER CRI. Immediate possession can be arranged. My lawyers can provide you, or whoever you may suggest, with all business and historical details. A word from you of acceptance or refusal is all that is necessary, and we can leave details to be thrashed out by our agents. Forgive me, won't you, for troubling you in the matter, and believe me, yours very sincerely.

"ARABELLA MARCH."

Adam read this over several times, and then, his mind being made up, he went to Mimi and asked if she had any objection. She answered-- after a shudder--that she was, in this, as in all things, willing to do whatever he might wish.

"Dearest, I am willing that you should judge what is best for us. Be quite free to act as you see your duty, and as your inclination calls. We are in the hands of God, and He has hitherto guided us, and will do so to His own end."

From his wife's room Adam Salton went straight to the study in the tower, where he knew Sir Nathaniel would be at that hour. The old man was alone, so, when he had entered in obedience to the "Come in," which answered his query, he closed the door and sat down beside him.

"Do you think, sir, that it would be well for me to buy Diana's Grove?"

"God bless my soul!" said the old man, startled, "why on earth would you want to do that?"

"Well, I have vowed to destroy that White Worm, and my being able to do whatever I may choose with the Lair would facilitate matters and avoid complications."

Sir Nathaniel hesitated longer than usual before speaking. He was thinking deeply.

"Yes, Adam, there is much common sense in your suggestion, though it startled me at first. I think that, for all reasons, you would do well to buy the property and to have the conveyance settled at once. If you want more money than is immediately convenient, let me know, so that I may be your banker."

"Thank you, sir, most heartily; but I have more money at immediate call than I shall want. I am glad you approve."

"The property is historic, and as time goes on it will increase in value. Moreover, I may tell you something, which indeed is only a surmise, but which, if I am right, will add great value to the place." Adam listened. "Has it ever struck you why the old name, 'The Lair of the White Worm,' was given? We know that there was a snake which in early days was called a worm; but why white?"

"I really don't know, sir; I never thought of it. I simply took it for granted."

"So did I at first--long ago. But later I puzzled my brain for a reason."

"And what was the reason, sir?"

"Simply and solely because the snake or worm WAS white. We are near the county of Stafford, where the great industry of china-burning was originated and grew. Stafford owes much of its wealth to the large deposits of the rare china clay found in it from time to time. These deposits become in time pretty well exhausted; but for centuries Stafford adventurers looked for the special clay, as Ohio and Pennsylvania farmers and explorers looked for oil. Anyone owning real estate on which china clay can be discovered strikes a sort of gold mine."

"Yes, and then--" The young man looked puzzled.

"The original 'Worm' so-called, from which the name of the place came, had to find a direct way down to the marshes and the mud- holes. Now, the clay is easily penetrable, and the original hole probably pierced a bed of china clay. When once the way was made it would become a sort of highway for the Worm. But as much movement was necessary to ascend such a great height, some of the clay would become attached to its rough skin by attrition. The downway must have been easy work, but the ascent was different, and when the monster came to view in the upper world, it would be fresh from contact with the white clay. Hence the name, which has no cryptic significance, but only fact. Now, if that surmise be true--and I do not see why not--there must be a deposit of valuable clay--possibly of immense depth."

Adam's comment pleased the old gentleman.

"I have it in my bones, sir, that you have struck--or rather reasoned out--a great truth."

Sir Nathaniel went on cheerfully. "When the world of commerce wakes up to the value of your find, it will be as well that your title to ownership has been perfectly secured. If anyone ever deserved such a gain, it is you."

With his friend's aid, Adam secured the property without loss of time. Then he went to see his uncle, and told him about it. Mr. Salton was delighted to find his young relative already constructively the owner of so fine an estate--one which gave him an important status in the county. He made many anxious enquiries about Mimi, and the doings of the White Worm, but Adam re-assured him.

The next morning, when Adam went to his host in the smoking-room, Sir Nathaniel asked him how he purposed to proceed with regard to keeping his vow.

"It is a difficult matter which you have undertaken. To destroy such a monster is something like one of the labours of Hercules, in that not only its size and weight and power of using them in little- known ways are against you, but the occult side is alone an unsurpassable difficulty. The Worm is already master of all the elements except fire--and I do not see how fire can be used for the attack. It has only to sink into the earth in its usual way, and you could not overtake it if you had the resources of the biggest coal-mine in existence. But I daresay you have mapped out some plan in your mind," he added courteously.

"I have, sir. But, of course, it may not stand the test of practice."

"May I know the idea?"

"Well, sir, this was my argument: At the time of the Chartist trouble, an idea spread amongst financial circles that an attack was going to be made on the Bank of England. Accordingly, the directors of that institution consulted many persons who were supposed to know what steps should be taken, and it was finally decided that the best protection against fire--which is what was feared--was not water but sand. To carry the scheme into practice great store of fine sea- sand--the kind that blows about and is used to fill hour-glasses-- was provided throughout the building, especially at the points liable to attack, from which it could be brought into use.

"I propose to provide at Diana's Grove, as soon as it comes into my possession, an enormous amount of such sand, and shall take an early occasion of pouring it into the well-hole, which it will in time choke. Thus Lady Arabella, in her guise of the White Worm, will find herself cut off from her refuge. The hole is a narrow one, and is some hundreds of feet deep. The weight of the sand this can contain would not in itself be sufficient to obstruct; but the friction of such a body working up against it would be tremendous."

"One moment. What use would the sand be for destruction?"

"None, directly; but it would hold the struggling body in place till the rest of my scheme came into practice."

"And what is the rest?"

"As the sand is being poured into the well-hole, quantities of dynamite can also be thrown in!"

"Good. But how would the dynamite explode--for, of course, that is what you intend. Would not some sort of wire or fuse he required for each parcel of dynamite?"

Adam smiled.

"Not in these days, sir. That was proved in New York. A thousand pounds of dynamite, in sealed canisters, was placed about some workings. At the last a charge of gunpowder was fired, and the concussion exploded the dynamite. It was most successful. Those who were non-experts in high explosives expected that every pane of glass in New York would be shattered. But, in reality, the explosive did no harm outside the area intended, although sixteen acres of rock had been mined and only the supporting walls and pillars had been left intact. The whole of the rocks were shattered."

Sir Nathaniel nodded approval.

"That seems a good plan--a very excellent one. But if it has to tear down so many feet of precipice, it may wreck the whole neighbourhood."

"And free it for ever from a monster," added Adam, as he left the room to find his wife.