The wireless equipment of the stations is of the usual type, and does not call for comment, but the apparatus on the trains is worth mention. The aerial, which must be low on account of bridges and tunnels, consists of rectangles of wire fixed at a height of 18 inches above the roof of each car. These separate aerials are connected together by a wire running to a small operating room containing a set of Marconi apparatus, and situated at the end of one of the cars. The earth connexion is made to the track rails, and the current is taken from the dynamos used to supply the train with electric light. With this equipment messages have been transmitted and received while the train was running at the rate of 70 miles an hour, and distances up to 125 miles have been covered. During a severe storm in the early part of last year the telegraph and telephone lines along the railroad broke down, but uninterrupted communication was maintained by wireless, and the operations of the relief gangs and the snow-ploughs were directed by this means. For emergency signalling this system is likely to prove of enormous importance. If signals are set wrongly, through some misunderstanding, and a train which should have been held up is passed forward into danger, it can be stopped by a wireless message in time to prevent an accident. Again, if a train has a breakdown, or if it sticks fast in a snow-drift, its plight and its exact position can be signalled to the nearest station, so that help may be sent without delay. The possibilities of the system in fact are almost unlimited, and it seems not unlikely that wireless telegraphy will revolutionize the long-distance railway travelling of the future. CHAPTER XXII ELECTROPLATING AND ELECTROTYPING