"The Quentin mine gets all cars needed. We demand our share and I shall insist upon the demand." The reply came: "I tell you we can't do it. I'll run down to your place to-morrow or next day and explain." "Don't want explanations," answered Duncan. "I want the cars." "But we simply can't furnish them." "But you simply must." "What if I refuse?" "Then I'll adopt other measures. But you won't refuse." "Why not?" "Because I know too much," answered Duncan. "I shall send to you by special messenger, on the train that will pass here within an hour, a letter making a formal tender of the freight. I make that tender by telegraph now, and you may as well accept it in that way. Your road is a chartered common carrier. Your lawyers will advise you that you cannot refuse freight formally tendered to you for carriage, unless you can show an actual inability; in that case you must show that you are doing your best by all shippers alike; that you are treating them with an equal hand. You perfectly well know you are not doing that. You know you have cars in plenty. You know you are deliberately discriminating against this mine, and in favor of its rival. I make formal demand, on behalf of the company I represent, for all cars needed for the shipment of this freight. If they are not forthcoming, as you say they will not be, I give notice that I will dump the coal by the side of your loading side-track and leave it there at your risk. Good-night." And Duncan shut off the telegraph instrument and devoted himself to the preparation of his letter of demand. It should be explained that the young man was not "making a bluff"--in the figurative phrase of that time and country--when he telegraphed in this way to the General Freight Agent. He had his facts well in hand. As soon as Davidson's intimation had come to him to the effect that the railroad officials were "standing in" with the proprietors of the Quentin mine, he had telegraphed for Joe Arnold to come to him by a train that would arrive at midnight. Joe Arnold was a detective of rare gifts and, incidentally, a reporter on a Chicago newspaper. Captain Will Hallam often had occasion to employ Joe, and thus Duncan had come into acquaintance with the young man's peculiar abilities for finding out things. Joe Arnold had an innocent, incurious, almost stupid countenance that suggested a chronic desire for sleep rather than any more alert characteristic. He had a dull, uninterested way of asking questions which suggested the impulse of a vacuous mind to "keep the talk going," rather than any desire to secure the information asked for. Indeed, when he asked a question and it was not promptly answered, he always hastened to say: "Oh, it's of no consequence, and it's none of my business." But before he quitted the presence of the man to whom the question had been put, Joe Arnold usually had his answer. To this man, when he came by the midnight train, Duncan said: