I had just come down from Bar Harbor. I had an artificial diamond made in Germany, and I was looking for Walker. Walker is chief of the United States Secret Service, and he knows more about artificial stones than any other man in America, unless it is Bartoldi. Gems are a fad with Walker, and a profession with Bartoldi. I do not know which of these motive impulses moves a man to the higher efficiency. The keen man with the fad gets to be an expert, and the necessities of trade makes the other one. Anyway, I wanted to show my diamond to both of them. I found Walker in the Forty-seventh National Bank on lower Fifth Avenue. He waved a recognition and went on with what he was saying to the cashier behind the grill: “There was no robbery; that’s what puzzles me. How did they get the thing? It’s lucky the bank discovered that it was missing almost immediately and sent out the word. The package had just come in, and was lying on a shelf under the bookkeeper’s desk.... But how did they get it?” And so I found Walker. Nobody would ever have taken Walker for the chief of the government Secret Service. In appearance he was the last person any one would have picked out for a secret agent. He looked like a practical person, and that is precisely what he was. You never could think that the man had any imagination; and he didn’t have any. At least, he didn’t have any imagination in the sense that we usually understand it. I suppose he had the kind of imagination that the inventor has, or the mathematician when he figures the orbit of the stars, or the engineer when he has to make some calculation on the stresses of a bridge. I asked him to look at my diamond when he came out. His face took on a decided expression of interest. “Go up and see Bartoldi,” he said. “I will be along in an hour.” He added with a sort of smile: “There is no leisure in my trade. Somebody’s always either robbing a national bank or trying to rob—boring from within or setting up some game on the outside.” Then he laughed. Now, that is how I happened to find Walker—just when I wanted to find him. By accident I stepped into something, as you would say. Well, it was not explained to me. In fact, to say plain truth, behind a lot of courteous indirections, he put me out of the bank and sent me up to Bartoldi’s to await his coming in an hour. I do not mean that he ordered me out. He enticed me out; he edged me out, a good deal as one would do with a child that had wandered into a rather tense conference. I went up to Bartoldi’s. Everybody knows where it is. He has a mammoth place on Fifth Avenue, rather far up—the trade is going up. The big retailers saw that a dozen years ago. Bartoldi is not the greatest jewel dealer in the world, but he is one of the greatest. The greatest jewel dealer in the world is Mahadol in Bombay; then come Vanderdick in Amsterdam, and Hauseman in Paris.