"The two diamonds in Wheeling and the two that turned up here are the only ones we know about," said the man in charge of the New York office. "The original Dillingham collection contained twenty-one rough stones--but whether the other seventeen have already been brought in or whether the people who are handling them have shipped them elsewhere is wholly problematical. The chief learned about the heart-shaped flaw from our man at Rotterdam, so that identifies one of the stones. But at the same time it doesn't help us in the least--for we can't handle the case from this end." "Same rules as on the Coast, eh?" inquired Marks. "Precisely. You've got to tackle the other end of the game. No rummaging around here, trying to pick up the trail that ends with the stone in Maiden Lane. As you know, this bunch is pretty well organized, wheels within wheels and fences on fences. You get something on one of them and the rest of the crowd will perjure themselves black in the face to get him off, with the result that your case will be laughed out of court and the man you're really after--the chap who's running the stones under your nose--is a thousand miles away with a grin on his face. You've got to land him first and the others later, if the chief wants them. The chances are, though, that he'll be well satisfied to have the goods on the crook that's doing the main part of the work." "Well," drawled Marks, "I trust he gets his satisfaction. Got any ideas on the matter?" "Nary an idea. The stones were sold abroad and presumably they were headed for Hamburg--which would appear to point to a German boat. Four of them, supposedly--one of them, certainly--turned up here without passing through the office or paying the customary duty. Now go to it!" When Marks got back to his hotel and started to think the problem over, he had to admit that there wasn't very much to "go to." It was the thinnest case he had ever tackled--a perfect circle of a problem, without the slightest sign of a beginning, save the one which was barred. Anxious as he was to make good, he had to concede that the department's policy of working from the other end of the case was the right course to follow. He had heard of too many arrests that fell flat, too many weary weeks of work that went for nothing--because the evidence was insufficient--not to realize the justice of the regulations that appeared to hamper him. "No," he thought, as he half dreamed over a pipe-load of tobacco, "the case seems to be impregnable. But there must be some way to jimmy into it if you try long enough."