The most extensive use of small pneumatic tubes in this country has been in our large retail department stores for despatching cash to and from a centrally located cashier’s desk. Seamless brass tubes are usually used, and, since the tubes are short, the air is either compressed or exhausted by means of positive rotary blowers. At the outlying stations the tubes are usually open to the atmosphere, while at the central station simple forms of valves are used for sending and receiving. An outgoing and a return tube are always used, and the air is kept in constant circulation. The carriers are of metal with felt packing rings and open on the side. These cash-carrying systems have come into use during the past twenty-five years. The Western Union Telegraph Company uses small tubes to transmit its messages to a considerable extent in some of our large cities. In 1876 four lines were laid in New York City from the main office on Broadway: two to the branch office at No. 14 Broad Street, one to 134 Pearl Street, and one to the Cotton Exchange. Since then this company has laid a double line about two miles in length under Broadway to its up-town office. It also uses tubes to send messages from the receiving desks to the operating rooms within the buildings. Many of our large hotels use pneumatic tubes to transmit messages to the different floors and offices of the buildings, taking the place of messenger, or bell boys, who formerly did this service. We call especial attention to the fact that in all the systems that we have mentioned which are in use both in this country and in Europe, none of the tubes are larger than three inches internal diameter; also that in all the systems, except in Paris where the carriers are despatched in trains, the carriers are so light and move so slowly that they can be stopped by allowing them to come in contact with some solid object, such as a box into which the carriers drop. Very few of the tubes are more than two miles in length, and most of them are less than one mile. A speed of more than thirty miles per hour has seldom been attempted, and usually it is much less than this. CHAPTER II. THE PNEUMATIC TRANSIT COMPANY AND THE FIRST PNEUMATIC TUBES FOR THE TRANSPORTATION OF UNITED STATES MAIL. =Organization.=—Early in the year 1892 several Philadelphia gentlemen organized a corporation and obtained a charter in the State of New Jersey to construct, lay, and operate pneumatic tubes for the transmission of United States mail, packages, merchandise, messages, etc., within the States of New Jersey and Pennsylvania. The corporation was styled the Pneumatic Transit Company. Mr. William J. Kelly was elected president, and the company is still under his management. [Illustration: WM. J. KELLY, President of the Pneumatic Transit Co.]