"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."
"Well," explained Humphrey, "the first thing to do in a criminal case is to take a good survey of the problem and the ground it covers—just as you do when you build a bridge, a dam, or open up a mine. The higher type of criminal investigator usually falls back upon his study and knowledge of criminology, which is a broader and more scientific development of the ordinary facts with which the city detective starts to work. What I am going to suggest to you is a new branch of criminology. For want of a better name at this time we'll call it Engineering-Criminology. I am not an engineer myself, and what I know about surveying and triangulation could be put into a thimble, but I think I know enough to give you an idea of what I mean.
"As I said before, the detectives are wallowing around in the mire of the lower West Side—they are in the valley, so to speak. Now, if you, as an engineer, were about to survey a certain unknown and inaccessible territory, you'd go up on the nearest high hill and pick out two other prominent points in the landscape, so as to form a triangle. Then you'd take sights, or whatever you would call it, from one point to another. A little figuring would give you the exact distance from one point to another, and a lot of information about the lay of the land in between. Am I not right?"