181:...a column of water be conveniently employed to transmit information. Mr. Francis Whishaw has conveyed a column of water through sixty yards of pipe in the most convoluted form, and the two ends of the column being on a level, motion is no sooner given to one end than it is communicated through the whole sixty yards to the other end of the column. No perceptible interval elapses between the time of impressing motion on one end of the column and of communicating it to the other. To each end of a column he attaches a float board with an index, and the depression of any given number of figures on one index, will be immediately followed by a corresponding rise of the float board and index at the other end. It is supposed that this simple longitudinal motion can be made to convey all kinds of information. It appears to us that the amount of information which can be conveyed by the motion in one direction only, of the water, or backward and forwards, must be limited. To make the mere motion backwards and forwards of a float board, indicated on a graduated index, convey a great number of words or letters, is the difficulty to be overcome.
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disappear into the vessels. When by experiment it is seen that the rapidity of escape is in both cases the same, the vessels are to be conveyed to the places in which both parties are to look after the signals and deposited there. Now whenever any of the contingencies written on the rods occurs he tells us to raise a torch and to wait until the corresponding party raises another. When both the torches are clearly visible the signaler is to lower his torch and at once allow the water to escape through the aperture. Whenever, as the corks sink, the contingency you wish to communicate reaches the mouth of the vessel he tells the signaler to raise his torch and the receivers of the signal are to stop the aperture at once and to note which of the messages written on the rods is at the mouth of the vessel. This will be the message delivered, if the apparatus works at the same pace in both cases.
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the middle of each cork should pass a rod graduated in equal section of three finger-breadths, each clearly marked off from the next. In each section should be written the most evident and ordinary events that occur in war, e.g., on the first, "Cavalry arrived in the country," on the second "Heavy infantry," on the third "Light-armed infantry," next "Infantry and cavalry," next "Ships," next "Corn," and so on until we have entered in all the sections the chief contingencies of which, at the present time, there is a reasonable probability in wartime. Next, he tells us to bore holes in both vessels of exactly the same size, so that they allow exactly the same escape.
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He says that those who are about to urgent news to each other by fire signal should procure two earthenware vessels of exactly the same width and depth, the depth being some three cubits and the width one. Then they should have corks made a little narrower than the mouths of the vessels and through
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at the bottom of their containers. Water would drain out until the water level reached the desired code, at which point the sender would signal with his torch, and the operators would simultaneously close their spigots. Thus the length of time between the sender's torch signals could be correlated
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While the Greek device was extremely limited in the codes (and hence the information) it could convey, the
British device was never deployed in operation other than for very short-distance demonstrations. Although the British device could be used in any visibility within its range of operation, it
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Although both systems employed water in their sending and receiver devices, their transmission media were completely different. The ancient Greek system transmitted its semaphoric information to the receiver visually, which limited its use to line-of-sight distances in good visibility
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Then we are to fill the vessels with water and put on the corks with the rods in them and allow the water to flow through the two apertures. When this is done it is evident that, the conditions being precisely similar, in proportion as the water escapes the two corks will sink and the rods will
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weather conditions only. The 19th-century
British system used water-filled pipes to effect changes to the water level in the receiver unit (similar to a transparent water-filled flexible tube used as a level indicator), thus limiting its range to the
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Aeneas, the author of the work on strategy, to find a remedy for the difficulty, advanced matters a little, but his device still fell far short of our requirements, as can be seen from his description of it.
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Whishaw, Francis. "Report of the Annual
Meeting of the British Association for the Advancement of Science, Volume 18, Parts 1848–1849: On The Uniformity Of Time And Other Telegraphs",
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To send a message, the sending operator would use a torch to signal the receiving operator; once the two were synchronized, they would simultaneously open the
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connected to each other; each container would be filled with water, and a vertical rod floated within it. The rods were inscribed with various predetermined
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could not work in freezing temperatures without additional infrastructure to heat the pipes. This contributed to its impracticality.
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The article concluded speculatively that the "... hydraulic telegraph may supersede the semaphore and the galvanic telegraph".
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Antique hydraulic telegraph: refinement of the data transfer rate in
Ancient Greece by an experiment and a mathematical model
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The system was estimated to cost £200 per mile (1.6 km) and could convey a vocabulary of 12,000 words. The U.K.'s
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Distant
Writing: A History of the Telegraph Companies in Britain between 1838 and 1868 - Non-Competitors
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A History of
Telegraph Companies In Britain Between 1838 And 1868: Whishaw's Hydraulic Telegraph
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A contemporary description of the ancient telegraphic method was provided by
Polybius. In
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The Civil
Engineer and Architect's Journal, Volume 1: Oct. 1837 to Dec. 1838: Miscellany
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Modern experiments show that the data transfer rate can achieve 151 letter per hour.
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The system involved identical containers on separate hills, which are
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The ancient Greek design was described in the 4th century BC by
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systems involving the use of water-based mechanisms as a
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that could be generated at the transmitter's device.
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243:, Distantwriting.co.uk website. Retrieved 2009-07-14
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The
Railway Magazine and Annals of Science, Vol. V.
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320:London: John Murray, 1849, p. 123.
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