A hot-box, it should be explained in passing, is caused by imperfect lubrication of the axles of cars or engines, at the point where they pass through the journal-bearings. As they revolve rapidly under the great weight upon them, the friction generates heat, unless the surfaces are properly oiled, and this heat causes the journal to swell until it sticks in the bearing and refuses to revolve at all. Not infrequently the heat is so great that it generates a flame and sets the car on fire. To keep the journal lubricated, it is enclosed in a metal box, called a journal-box, and this is filled with axle-grease, or "dope," as railroaders call it. In every railroad yard where trains are made up, there is a gang of men whose sole business it is to go from car to car, dope-bucket in hand, and make sure that all journal-boxes are properly filled. For hot-boxes are a prolific source of trouble. So are burst air-hose. Air-brakes, operated by compressed air, are very generally in use now on freight-cars as well as passenger-coaches. The compressed air is carried under the cars in iron pipes, but the coupling is of rubber-hose, in order to allow some play as the cars bump together or strain apart, and this hose frequently bursts under the great pressure. A burst hose instantly sets all the brakes, and the train-hands must first find the break, and then replace the burst coupling with a new one. Mr. Schofield had listened to all these explanations with furrowed brow. Now he turned abruptly to the conductor. "When you found you had run over your time," he demanded, "how does it come you proceeded without a flag?" "We hadn't run over our time," protested the conductor, hotly. "We had till 7.08 to make the Junction. We supposed of course the operator here knew his business and would protect us." "You would have been protected if I'd known you were coming," said Allan, quickly, "but I had no order for you." "What!" demanded the engineer, incredulously, "do you mean to say th' dispatcher didn't cover us?" "I certainly do." "An' you didn't git no order fer th' special to meet us here?" "I got no order whatever." The engineer, his face very red, produced from his pocket a soiled piece of tissue-paper. "Read that," he said, and handed it to the trainmaster. Mr. Schofield opened it, his face very stern. "'Engine 618,'" he read, "'will run extra from West Junction to Byers Junction and will keep clear of special passenger-train west, engine 315, after 7.08 P. M.'" "We'd have got here all right at 7.06," went on the engineer, truculently. "We had three minutes." "What time did the special pass?" asked Mr. Schofield. "At 7.05," answered Allan. The trainmaster nodded, and handed the order back to the engineer. "You boys are all right," he said. "You're evidently not to blame." The engineer chuckled. "You bet we ain't," he agreed. "But that'll be th' last o' Mister Dispatcher on this road, I reckon. Who was it?"