The London system has grown until it now includes no less than forty-two stations and thirty-four miles of tubes. Similar systems have been established in connection with the telegraph in Liverpool, Manchester, Birmingham, Glasgow, Dublin, and New Castle. The tubes give a cheaper and more rapid means of despatching telegrams between sub-stations and central stations than transmission by telegraph, and local telegrams can be delivered in the sender’s handwriting. =An Underground Pneumatic Railway for Transportation of Mail.=—Before describing the systems used in the cities on the Continent of Europe, we must notice a very large pneumatic tube, or more properly called a pneumatic tunnel railway, constructed in London for the transportation of mail from one of the railway stations. The first railway of this type was constructed in 1863 by the Pneumatic Despatch Company of London, and extended from Euston to the district post-office in Eversholt Street, a distance of about eighteen hundred feet. The tunnel was flat on the bottom, having a D-shaped cross-section two feet eight inches by two feet eight inches. The carriers or carriages were cradle-like boxes fitting the tunnel, and they moved at a speed of seventeen miles per hour, carrying fifteen mails daily. In 1872 two similar but larger tunnels were built from Euston Station to the general post-office, a distance of fourteen thousand two hundred and four feet, or two and three-quarters miles. One was for the up traffic, and the other for the down. The tunnels were four and a half feet wide by four feet high, the straight part being built of cast iron and the bends of brick. The line was operated by a fan twenty-two feet in diameter, which forced the air into one tunnel and exhausted it from the other, producing a vacuum of ten inches of water, or six ounces per square inch. The carriages occupied twelve minutes in traversing the tunnels, and there was one gradient of one to fourteen. The carriages were ten feet four inches long and weighed twenty-two hundredweight. “The system was able to transport over the whole line, allowing for delays, an average of a ton per minute.” The system was used to transport the mails in bulk, but it was found to be slow and unsatisfactory, and was very soon abandoned.