PNEUMATIC DISPATCH. 138 PNEUMATIC DISPATCH. for sucopetliiig statiims are insprteil. The speeds of the trainsare from li) to 23 milc3 per hour. Vienna, Austria, has a pneumatic dispatch sys- tem rc-enilplinnr that of Paris. The London s.vstem of pneumatic dispatch difTers from those of Continental cities just men- tioned chielly in being a radial system instead of a circuit system. The tubes radiate from a central power station to substations located at various points. In 1897 the system comprised 42 stations and .34 miles of tubes. The first London tube was installed by Siemens Bros., in 1870. but the present lines have been greatly improved over the original construction. Other British cities which have systems of pneumatic dispatch are Liverpool, Manchester, Birmingham, Glas- gow, Dublin, and Newcastle. Mention should be made of the atmospheric railway built in Lon- don in ISd.'J, from Kuston to a station in Ever- shalt Street, 1800 feet, and extended in 1.S72 from Euston to the General Post-office, 14,204 feet. The original tunnel was a single tunnel flat on the bottom and D-shaped in section 273 feet high and 2'-^i, feet wide. The carriers were cradlc-liUo boxes fitting the tunnel and they were moved at a speed of 17 miles per hour. The second line built was a double tunnel line each 4 feet high and 4% feet wide. These atmospheric railways were used to carry the mails for a time, but were found to be slow and expensive and were aban- doned. 1893 the United States I'ost-oilici' Department in- stalled pneumatic disjiatch hetween its ;iiain post-oflice and its substation at the Bourse. Phila- delphia. This line is 2974 feet long, with tul>es eiglit inches in diameter, and the carriers travel at a speed of about 25 miles per hour. This sys- tem has since been extended to reach the ter- minal stations of the Pennsylvania and the Phila- delphia and Reading railways. In 1897-98 there were installed 6.8.3 miles of pneumatic dispatch connecting the general post-olliee in Xew York City with the Brooklyn post-offife, the Grand Central Station, and intermediate sibstations. As the result of the experience with these linos. Congress, by an act dated June 2, 1900, ordered a committee of experts to be appointed to investi- gate and report upon the cost, construction, and utility of such systems for these and other large cities. This committee investigated these ques- tions for eleven large cities and submitted a voluminous report in 1901. The Batcliiller system, which was first installed at Xew York and Philadelphia, on the lines in use in 1901, employed compressed air .at a pres- sure of from five to ten pounds. The compressed air may be furnished by any improved type of air compressor or high-pressure blower and forces the carriage through a cast-iron pipe which is bored true and smooth and carefully jointed. The tubes, which are six and eight inches in di- ameter, are laid in a double line to facilitate ^^^^^^^^^^^^^^^^^^^^^^^^ BE.NDISG AND BECEI^INQ APPARATUS. Perhaps the first attempt at pneumatic dis- patch in America was made by A. E. Beach, who invented and exliibited a full-size working model of an atmospheric railway in 1807. Some years later Jlr. Beach began the construction of an atmospheric railway tunnel under Broadway, New Y'ork City, and had completed a short dis- tance of tunnel when the work was abandoned. In his working model Mr. Beach used a tube six feet in diameter through which a car seating ten persons was propelle<l by air pressure generated by a fan. This is the only attempt actually made in America at atmospheric railway con- struction. The use of pneumatic dispatch has, however, became quite extended. Perhaps the most extensive use is of small pneumatic tubes in stores for dispatching cash to and from a cen- trall.v located cashier's desk. Seamless brass tubing is generally used and the power is sup- plied by rotary blowers. Tlie Western Union Telegraph Company has pneumatic dispatch sys- tems in use in Xew York and Chicago, and simi- lar private systems are in use elsewhere. In traflSc in opposite directions. The carriers are symmetrical in form, of the shape shown in the illustration, and of a diameter about one inch less than that of the tube. A door in the end of each carrier gives access to the interior. They are from 16 to 30 inches in length and weigh from 7 to 16 pounds. N^ear each end are placed packing rings of cotton fabric secured to the SECTION OF CARRIEK. main body by metal collars so as to insure a close fit in the tube. These packing rings are lubricatedjby vaseline, which makes easy running possible. The sending and receiving apparatus, which is located at each end and also at inter- mediate stations on the line, is shown in the il-
