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Along with progress in other electrical devices has come the invention of a practical printing telegraph machine. For years effort has been expended to produce a contrivance that would print automatically from electrical impulses sent over a wire from a distance, but the devices have operated poorly. To be sure, the stock "ticker" serves its purpose in a measure, and when not out of order, is worthy of great commendation. The mechanism, however, is so complicated that the machine cannot be relied upon. Now comes from Australia a man named Donald Murray, who with great ingenuity, has perfected a device which to-day operates in the offices of the Postal Telegraph Company in many cities and before Iong probably will find its way over two continents. Labor saving is not so much the result aimed at and reached in this instrument as the tremendous saving in wire. When it is considered that a single copper wire from New York to Chicago costs $60,000, that it rents for $12,000 a year, and that the Murray system can, on one line, do the business of two or three, the saving may be imagined readily. This device, the Page-Printing Telegraph, is a series of instruments which automatically receive upon a typewriter telegrams sent over a single wire. There are four main instruments for sending and receiving--two for each station. The sending instruments consist of a transmitting perforator and a modified Wheatstone transmitter. The receiving devices are a receiving perforator and an automatic typewriting attachment. Upon receiving a message for transmission, the operator sends it through the perforator, which is much like a typewriter. This device punctures a tape with little dots at irregular intervals. The arrangement of these dots signifies certain letters. The perforator writes eighty-four characters. The tape is provided also with a central line of smaller punctures, which engage the teeth of feed-wheels, in the machines, thus insuring a steady flow as they are drawn through mechanically. After the message has been perforated on the tape, the tape is fed through the transmitter. This instrument is so arranged that two small rods press against the tape, held in place by small springs. When the rods are even with the perforations they push through for a moment and then are, withdrawn automatically. These rods serve to make and break an electrical current. This current is imparted to the wire, traveling as irregular impulses according to the spacing of the perforations. These impulses pass as signals to the receiving station. The process of receiving the message is similar to that of its transmission, excepting that the latter is done by hand, whereas the former results from electrical energy. To aid in the receiving operation, there is a local electrical circuit. On this line are a punching relay, a governing relay, a vibrator, a receiving perforator and the automatic typewriter The message arrives on the wire and the impulses are transformed into the local receiving circuit. Automatically, the punching machine perforates the series of irregular dots in the receiving tape. The tape is then fed into the typewriter, which is so arranged that the perforations cause the proper keys to be lifted and the message to be printed in commercial form. The speed of the system is remarkable. The ordinary Morse system permits of about 25 words a minute. Under similar conditions, the Page-Printing Telegraph transmits and receives about 130 words during the same interval. The perforators can receive messages faster than the typewriting machine can translate them in commercial form, but this is no drawback, as the tape at the receiving station can be torn at certain intervals and fed into several machines at once. The design of Murray's skilfully contrived apparatus, filed November 28, 1899, in the United States Patent Office, indicates how striking is the contrast between its delicate simplicity of construction and its great importance to telegraphy. Since he perfected the instrument, however, the inventor has made claim for 37 distinct improvements on its various parts, which are now covered by three separate patents. The value of the invention in facilitating the operations of the Postal Telegraph Cable Company, to which the ownership of the patent was assigned, cannot be overestimated. TIN-MAKING IN THE TWENTIETH CENTURY |