"In my opinion," Humphrey explained, "the police have fallen down so far on this case because they are sticking too close to the rules. The average city detective becomes familiar with the ways of the average thug-type of criminal. Give him an ordinary murder, burglary, or blackmailing case and he knows just about where to go to get his hands on the people he wants. But when a different class of criminal begins to operate, the average detective cannot see the new conditions. He goes floundering along the same old lines and lets real clues slip through his fingers." Humphrey paused to relight his cigar. "Go on," again urged Forrester. "I am learning something." "Now," continued Humphrey, "the crooks that compose the ’Friends of the Poor’ have been operating for about one year. In that time they have received various sums running from ten thousand to twenty-five thousand dollars. I venture to say that in one year’s time they have taken in pretty close to two hundred thousand dollars! Now, I ask you, Mr. Forrester; if you were taking in that amount of money, where would you have your hangout? In some West Side saloon or tenement, or in a high class neighborhood—perhaps even in some fine hotel? Do you get my thought, Mr. Forrester?" "I think I do," said Forrester. "All right, then," went on Humphrey. "I happen to know what the police are doing in this matter. They are dividing their time between watching an old oak up on the North Shore, and rummaging around West Side dives. Somewhere, _in between_, our men sit laughing at them!" "I am strongly inclined to believe you are right, Mr. Humphrey," assented Forrester. "But the important question is: How are we going to locate that place which lies in between?" "That’s where you come in," maintained Humphrey. "That’s where your money, social position, training and brains are going to enable you to give the ordinary detectives the go-by. When you mentioned becoming a detective, an idea hit me with an awful wallop. Now, Mr. Forrester, you’re an engineer." "How did you know that?" queried Forrester. "We usually look up a man before we interview him. We know all about you." "I see," smiled Forrester. "Well, then, as an engineer how am I going to solve this problem in crime?" "By triangulation!" exclaimed Humphrey. Forrester laughed. "Now you _have_ got me guessing, Mr. Humphrey. As a civil engineer I have used triangulation in my surveying work on many occasions, but how I can apply it to a criminal problem is beyond me."