"We know all about everything," Grady said gravely. "We have been tracking Fenwick for years, and it is a terrible indictment we shall have to lay against him when the proper time comes. We shall prove beyond the shadow of a doubt that he was one of the murderers of Mr. George Le Fenu --but we need not go into that now, for I see you are anxious to know all about the trick of the sovereigns. After Fenwick was compelled to abandon the Four Finger Mine, he found himself with a great deal less gold than he had expected. Then he hit upon the ingenious scheme which we are here to expose. His plan was to make sovereigns and half-sovereigns, and put them on the market as genuine coins. Now do you see what he had to gain by this ingenious programme?" CHAPTER XXIV THE MOUTH OF THE NET "I am afraid I am very dense," Venner said, "but I quite fail to see how a man could make a fortune by selling for a sovereign an article that cost him twenty shillings, to say nothing of the trouble and cost of labor and the risk of being discovered--" "As a matter of fact, the risk is comparatively small," Grady said. "It was only by a pure accident that we got on the inside track of this matter. You see, the coins are of actual face value, they are most beautifully made, and, indeed, would pass anywhere. Let me tell you that every sovereign contains a certain amount of alloy which reduces its actual value to about eighteen and threepence. Now you can see where the profit comes in. Supposing these men turn out a couple of thousand sovereigns a day--no very difficult matter with a plant like theirs; and, of course, the money can be disposed of with the greatest possible ease. This leaves a profit of a hundred and seventy-five pounds a day. When I have said so much, I think I have told you everything. Don't you admire the ingenuity of an idea like this?" It was all perfectly plain now--indeed, the mystery appeared to be ridiculously simple now that it was explained. "And what are you going to do now?" Venner asked. Grady explained that the next step would be the arrest of Fenwick and his gang at Merton Grange. For that purpose it would be necessary to enlist the assistance of the local authorities. And in no case did the American detectives purpose to effect the arrest before night. So far as Venner was concerned, he was quite at liberty to accompany the Americans on their errand; at the same time they let him infer that here was a situation in which they preferred his room to his company. "As you will," Venner smiled. "So far as I am concerned, I am going to get back to Canterbury as soon as I can. With all your preparations you have an exceedingly clever man to deal with, and it is just possible that by this time Fenwick already knows that you have laid the messenger by the heels. Men of that sort never trust one another, and it is exceedingly probable that Blossett has been watched."