Venner sat just for a moment or two with the thin stream trickling through his fingers, and wondering what it all meant. With his superior knowledge of past events, he could see in this something that it was impossible for Gurdon to follow.

"I suppose this is some of the gold from the Four Finger Mine?" Gurdon suggested. "Do you know, I have never handled any virgin gold before. I had an idea that it was more brilliant and glittering. Is this very good stuff?"

"Absolutely pure, I should say," Venner replied. "There are two ways of gold mining. One is by crushing quartz in machinery, as they do in South Africa, and the other is by obtaining the metal in what are called pockets or placers. This is the way in which it is generally found in Australia and Mexico. I should not be in the least surprised if this came from the Four Finger Mine."

"There is no reason why it shouldn't," Gurdon said. "It is pretty evident, from what you told me last night, that Mark Fenwick has discovered the mysterious treasure house, but that does not account for all these proceedings. Why should he have taken all the trouble he did last night, when he might just as well have brought the stuff in, and taken the other boxes out by the front door?"

"That is what we have to find out," Venner said. "That fellow may call himself a millionaire, but I believe he is nothing more nor less than a desperate adventurer."

Gurdon nodded his assent. There must have been something very urgent to compel Mark Fenwick to adopt such methods. Why was he so strangely anxious to conceal the knowledge that he was receiving boxes of pure gold in the hotel, and that he was sending out something of equal value? However carefully the thing might have been planned the drugging of lift attendants must have been attended with considerable risk. And the slightest accident would have brought about a revelation. As it was, everything seemed to have passed off smoothly, except for the chance by which Gurdon had stumbled on the mystery.

"We can't leave the thing here," the latter said. "For once in my life I am going to turn amateur detective. I have made up my mind to get into Fenwick's suite of rooms and see what is going on there. Of course, the thing will take time, and will have to be carefully planned. Do you think it is possible for us to make use of your wife in this matter?"

"I don't think so," Venner said thoughtfully.

"In the first place, I don't much like the idea; and in the second, I am entirely at a loss to know what mysterious hold Mark Fenwick has on Vera. As I told you last night, she left me within a very short time of our marriage, and until a few hours ago I had never looked upon her again. Something terrible must have happened, or she would never have deserted me in the way she did. I don't for a moment believe that Mark Fenwick knew anything about our marriage, but on that point I cannot be absolutely certain. You had better come back to me later in the day, and I will see what I can do. It is just possible that good fortune may be on my side."

The afternoon was dragging on, and still Venner was no nearer to a practical scheme which would enable him to make an examination of Fenwick's rooms without the chance of discovery. He was lounging in the hall, smoking innumerable cigarettes, when Fenwick himself came down the stairs. Obviously the man was going on a journey, for he was closely muffled up in a big fur coat, and behind him came a servant, carrying two bags and a railway rug. It was a little gloomy in the lobby, so Venner was enabled to watch what was going on without being seen himself. He did not fail to note a certain strained anxiety that rested on Fenwick's face. The man looked behind him once or twice, as if half afraid of being followed. Venner had seen that same furtive air in men who are wanted by the police. Fenwick stopped at the office and handed a couple of keys to the clerk. His instructions were quite audible to Venner.

"I shan't want those for a day or two," he said. "You will see that no one has them under any pretext. Probably, I shall be back by Saturday at the latest."

Venner did not scruple to follow Fenwick's disappearing figure as far as the street. He was anxious to obtain a clue to Fenwick's destination. Straining his ears, he just managed to catch the words "Charing Cross," and then returned to the hall, by no means dissatisfied. Obviously, Fenwick was intending to cross the Channel for a day or two, and he had said to the clerk that he would not be back before Saturday.

Here was something like a chance at last. Very slowly and thoughtfully, Venner went up the stairs in the direction of his own room. He had ascertained by this time that one part of Fenwick's suite was immediately over his own bedroom. His idea now was to walk up to the next floor, and make a close examination of the rooms there. It did not take him long to discover the fact that Fenwick's suite was self contained, like a flat. That is to say, a strong outer door once locked made communication with the suite of rooms impossible. Venner was still pondering over his problem when the master door opened, and Vera came out so hurriedly as almost to fall into Venner's arms. She turned pale as she saw him; and as she closed the big door hurriedly behind her, Venner could see that she had in her hand the tiny Yale key which gave entrance to the suite of rooms. The girl looked distressed and embarrassed, but not much more so than Venner, who was feeling not a little guilty.

But all this was lost upon Vera; her own agitation and her own unhappiness seemed to have blinded her to everything else.

"What are you doing here?" she stammered.

"Perhaps I am looking for you," Venner said. He had quite recovered himself by this time. "I was in the lobby just now, when I saw that scoundrel, Fenwick, go out. He is not coming back for a day or two, I understand."

"No," Vera said with accents of evident relief. "He is gone, but I don't know where he is gone. He never tells me."

Just for a moment Venner looked somewhat sternly at his companion. Here was an opportunity for an explanation too good to be lost.

"There is a little alcove at the end of the corridor," he said. "I see it is full of ferns and flowers. In fact, the very place for a confidence. Vera, whether you like it or not, I am going to have an explanation."

The girl shrank back, and every vestige of color faded from her face. Yet at the same time, the pleading, imploring eyes which she turned upon her companion's face were filled with the deepest affection. Badly as he had been treated, Venner could not doubt for a moment the sincerity of the woman who had become his wife. But he did not fail to realise that few men would have put up with conduct like this, however much in love they might have been. Therefore, the hand that he laid on Vera's arm was strong and firm, and she made no resistance as he led her in the direction of the little alcove.

"Now," he said. "Are you going to tell me why you left me so mysteriously on our wedding day? You merely went to change your dress, and you never returned. Am I to understand that at the very last moment you learned something that made it absolutely necessary for us to part? Do you really mean that?"

"Indeed, I do, Gerald," the girl said. "There was a letter waiting for me in my bedroom. It was a short letter, but long enough to wreck my happiness for all time."

"No, no," Venner cried; "not for all time. You asked me to trust you absolutely and implicitly, and I have done so. I believe every word that you say, and I am prepared to wait patiently enough till the good time comes. But I am not going to sit down quietly like this and see a pure life like yours wrecked for the sake of such a scoundrel as Fenwick. Surely it is not for his sake that you—"

"Oh, no," the girl cried. "My sacrifice is not for his sake at all, but for that of another whose life is bound up with his in the strangest possible way. When you first met me, Gerald, and asked me to be your wife, you did not display the faintest curiosity as to my past history. Why was that?"

"Why should I?" Venner demanded. "I am my own master, I have more money than I know what to do with and I have practically no relations to consider. You were all-sufficient for me; I loved you for your own sake alone; I cared nothing, and I care nothing still for your past. What I want to know is, how long this is going on?"

"That I cannot tell you," Vera said sadly. "You must go on trusting me, dear. You must—"

The speaker broke off suddenly, as someone in the corridor called her name. She slipped away from Venner's side, and, looking through the palms and flowers, he could see that she was talking eagerly to a woman who had the appearance of a lady's maid. Venner could not fail to note the calm strength of the woman's face. It was only for a moment; then Vera came back with a telegram in her hand.

"I must go at once," she said. "It is something of great importance. I don't know when I shall see you again—"

"I do," Venner said grimly. "You are going to dine with me to-night. Come just for once; let us imagine we are on our honeymoon. That blackguard Fenwick is away, and he will be none the wiser. Now, I want you to promise me."

"I really can't," Vera protested. "If you only knew the danger—"

However, Venner's persistency got its own way. A moment later Vera was hurrying down the corridor. It was not until she was out of sight that Venner found that she had gone away, leaving the little Yale key behind her on the table. He thrilled at the sight of it. Here was the opportunity for which he had been waiting.

Not more than ten minutes had elapsed when, thanks to the use of the telephone, Gurdon had reached the Grand Empire Hotel. In a few hurried words, Venner gave him a brief outline of what had happened. There was no time to lose.

"Of course, it is a risk," Venner said, "and I am not altogether sure that I am justified in taking advantage of this little slip on the part of my wife. What do you think?"

"I think you are talking a lot of rot," Gurdon said emphatically. "You love the girl, you believe implicitly in her, and you are desperately anxious to get her out of the hands of that blackguard, Fenwick. From some morbid idea of self sacrifice, your wife continues to lead this life of misery rather than betray what she would probably call a trust. It seems to me that you would be more than foolish to hesitate longer."

"Come along, then," Venner said. "Let's see what we can do."

The key was in the lock at length, and the big door thrown open, disclosing a luxurious suite of rooms beyond. So far as the explorers could see at present, they had the place entirely to themselves. No doubt Fenwick's servants had taken advantage of his absence to make a holiday. For the most part, the rooms presented nothing out of the common; they might have been inhabited by anybody possessing large means. In one of the rooms stood a desk, carefully locked, and by its side a fireproof safe.

"No chance of getting into either of those," Gurdon said. "Besides, the attempt would be too risky. Don't you notice a peculiar noise going on? Sounds almost like machinery."

Surely enough, from a distant apartment there came a peculiar click and rumble, followed by a whirr of wheels, as if someone was running out a small motor close by. At the same time, the two friends noticed the unmistakable odor of petrol on the atmosphere.

"What the dickens can that be?" Gurdon said. "Its most assuredly in the flat, and not far off, either."

"The only way to find out is to go and see," Venner replied. "I fancy this is the way."

They came at length to a small room at the end of a long corridor. It was evidently from this room that the sound of machinery came, for the nearer they came the louder it grew. The door was slightly ajar, and looking in, the friends could see two men, evidently engaged on some mechanical task. There was a fire of charcoal in the grate, and attached to it a pair of small but powerful bellows, driven by a small motor. In the heart of the fire was a metal crucible, so white and dazzling hot that it was almost impossible for the eye to look upon it. Venner did not fail to notice that the men engaged in this mysterious occupation were masked; at least, they wore exceedingly large smoked spectacles, which came to much the same thing. Behind them stood another man, who had every appearance of being a master workman. He had a short pipe in his mouth, a pair of slippers on his feet, and his somewhat expansive body was swathed in a frock coat. Presently he made a sign, and with the aid of a long pair of tongs, the white hot crucible was lifted from the fire. It was impossible for the two men outside to see what became of it, but evidently the foreman was satisfied with the experiment, for he gave a grunt of approval.

"I think that will do," he muttered. "The impression is excellent. Now, you fellows can take a rest whilst I go off and finish the other lot of stuff."

"He's coming out," Venner whispered. "Let us make a bolt for it. It won't do to be caught here."

They darted down the corridor together, and stood in an angle of a doorway, a little undecided as to what to do next. The man in the frock coat passed them, carrying under one arm a square case, that bore some resemblance to the slide in which photographers slip their negatives after taking a photograph. The man in the frock coat placed his burden on a chair, and then, apparently, hurried back for something he had forgotten.

"Here is our chance," Gurdon whispered. "Let's see what is in that case.
There may be an important clue here."

The thing was done rapidly and neatly. Inside the case, between layers of cotton wool, lay a great number of gold coins, obviously sovereigns. They appeared to be in a fine state of preservation, for they glistened in the light like new gold.

"Put one in your pocket," whispered Venner.

"I'm afraid we are going to have our journey for our pains; but still, you can't tell. Better take two while you are about it."

Gurdon slipped the coins into his pocket, then turned away in the direction of the door as the man in the frock coat came back, thoughtfully whistling, as if to give the intruders a chance of escape. Before he appeared in sight the outer door closed softly, and Venner and Gurdon were in the corridor once more.