"Not so much as you think, my boy, for there are not any great amount of diamonds in the market at any one time. The yield of the South African fields regulates the price. I have had this idea in my head for some time, and have studied the details. Of course, I should not attempt to buy in all the diamonds that are in the market. A small portion of them would yield profit enough to float the firm off again." "But if you have only a part of the supply in your hands, how are you to regulate the market value? You must come down to the prices at which other holders are selling." "Ha! Ha! Very good! very good!" the old merchant said, shaking his head good-humouredly. "But you don't quite see my plan yet. You have not altogether grasped it. Allow me to explain it to you." His son lay back upon the sofa with a look of resignation upon his face. Girdlestone continued to stand upon the hearth-rug and spoke very slowly and deliberately, as though giving vent to thoughts which had been long and carefully considered. "You see, Ezra," he said, "diamonds, being a commodity of great value, of which there is never very much in the market at one time, are extremely sensitive to all sorts of influences. The value of them varies greatly from time to time. A very little thing serves to depreciate their price, and an equally small thing will send it up again." Ezra Girdlestone grunted to show that he followed his father's remarks. "I did some business in diamonds myself when I was a younger man, and so I had an opportunity of observing their fluctuations in the market. Now, there is one thing which invariably depreciates the price of diamonds. That is the rumour of fresh discoveries of mines in other parts of the world. The instant such a thing gets wind the value of the stones goes down wonderfully. The discovery of diamonds in Central India not long ago had that effect very markedly, and they have never recovered their value since. Do you follow me?" An expression of interest had come over Ezra's face, and he nodded to show that he was listening. "Now, supposing," continued the senior partner, with a smile on his thin lips, "that such a report got about. Suppose, too, that we were at this time, when the market was in a depressed condition, to invest a considerable capital in them. If these rumours of an alleged discovery turned out to be entirely unfounded, of course the value of the stones which we held would go up once more, and we might very well sell out for double or treble the sum that we invested. Don't you see the sequence of events?" "There seems to me to be rather too much of the 'suppose' in it," remarked Ezra. "How do we know that such rumours will get about; and if they do, how do we know that they will prove to be unfounded?"