quick-acting brake to freight cars. The performance of this train was to railroad men most impressive. A freight train of fifty cars is about one-third of a mile long. To see such a train, running forty miles an hour, smoothly stopped in one-third of its own length, without shock or fuss, was an object-lesson that no one could fail to understand or to remember. Some of the stops made by this train will give a fair notion of the relative power of hand- and air-brakes for quick stops. The following figures are averages of stops made in six different cities. They give the distances run in feet from the instant of applying the brakes till the train was brought to a stand-still: Feet. Hand-brakes, 50 cars, 20 miles an hour 794 Air-brakes, 50 cars, 20 miles an hour 166 Air-brakes, 50 cars, 40 miles an hour 581 Air-brakes, 20 cars, 20 miles an hour 99 With twenty cars at twenty miles an hour even shorter stops were made than those recorded above. In the Burlington trials the hand-brake stops, with fifty-car trains at forty miles an hour, were made in from two thousand five hundred to three thousand feet. [Illustration: Dwarf Semaphores and Split Switch.] The air-brake is somewhat complicated, but the complicated mechanism is strong, has little movement, and is securely protected from dirt and the elements. It is therefore little liable to derangement. It is, however, becoming better understood that brake-gear must be good, and employees carefully instructed in the care and use of the air-brake to get its best results; and in recent years two or three elaborate instruction-cars have been fitted up for the education of the enginemen and trainmen. Space does not permit more than an allusion to driver-brakes, which are operated by steam and by air. The forms in constant use are made by the Eames, the American, the Westinghouse, and the Beals companies. Nor can much be said here of the water-brake, used to some extent on locomotives working heavy grades. It consists of a simple arrangement of admitting a little hot water, instead of steam, to the cylinders. The engine is reversed and the cylinder-cocks are opened to the air. The cylinders then act as air-pumps, and the retarding effect is due to the back pressure. The use of the water is to prevent overheating of the parts. [Illustration: Semaphore Signal with Indicators. (One arm governs several tracks. The number of the track which is clear is shown on the indicator disk.)]