"For example; take Mr. Nevins, who was the last victim of the ’Friends of the Poor,’ as the first point of your triangle. Take his bank as the second, and his home as the third point. Instead of measuring the distance between these points by feet or rods, measure it by people and events. Set down, just as you would the figures of a survey, the names of his friends and acquaintances, the men with whom he has done business, and any little out-of-the-way events which have taken place in his life, so far as you can ascertain them. Do this with the other people who have been concerned in the blackmailing activities of this band. By arranging your triangles so they will overlap if possible, you will get at a starting point. _Somewhere the lines will cross_, and at the point of intersection a definite clue may form." "Mr. Humphrey," laughed Forrester, "you are giving me a man’s-size job." "I know it!" admitted Humphrey. "But the man who solves this case has got to put more than ordinary brains and ability into it. You have got to forget the old rules and theories and formulas. That is why the experienced detectives are falling down. They can’t forget the rules! When you suggested a while ago that you thought of turning detective, I immediately saw its possibilities. Your engineering training has taught you how to study cause and effect, and work out plans for meeting unusual conditions. You start with a mind trained to solve difficult problems, but at the same time your mind is free of all the traditions of the detective craft. Things they wouldn’t notice, or consider important if they did, will impress themselves upon you and start a train of thought. "Now then," exclaimed Humphrey, jumping to his feet, "I have over-stayed my welcome and I must get back to the office and write up my story for tomorrow’s paper. You can rest assured, however, that the important details of this conversation will not get into print until you say the word. But remember, when the big scoop comes—_it belongs to me!_" "I promise you that," returned Forrester, rising and extending his hand. "We’ll shake hands on it." "And you may count on me to help all I can in the meantime," declared Humphrey, as he grasped Forrester’s hand. "Let me offer you a suggestion for that article which is to appear tomorrow," said Forrester. "Shoot!" replied Humphrey. "Announce that I have given up all idea of fighting the ’Friends of the Poor,’ and say that Saturday, before midnight, I shall place a package containing the money in that tree." "I get you," smiled Humphrey. "I’ll be there!" CHAPTER IV—THE CAR IN THE FOG Forrester glanced at his watch. It was just nine o’clock, not too late to make his promised call on the Nevins.