ca 62 __ « Pneumatika » — Hydraulis
‣ Comment : A collection of around 80 mechanical apparatus, that work with air, steam or hydraulic pressure. This includes a fire extinction apparatus, automata that provide water if a coin is inserted and the first steam engine (Aeolipile). The Heronball, Thermoscope, Syphon, Fountain, and Aeolipile. “The investigation of the properties of Atmospheric Air having been deemed worthy of close attention by the ancient philosophers and mechanists, the former deducing them theoretically, the latter from the action of sensible bodies, we also have thought proper to arrange in order what has been handed down by former writers, and to add thereto our own discoveries : a task from which much advantage will result to those who shall hereafter devote themselves to the study of mathematics. We are further led to write this work from the consideration that it is fitting that the treatment of this subject should correspond with the method given by us in our treatise, in four books, on water-clocks. For, by the union of air, earth, fire and water, and the concurrence of three, or four, elementary principles, various combinations are effected, some of which supply the most pressing wants of human life, while others produce amazement and alarm.”. — (excerpt of the Preface). Heron of Alexandria, who lived in the first century AD, wrote an extended treatise on Pneumatics, in which he described his use of pneumatic power to control a variety of mechanisms, including automata and whistling birds. It is clear that his birds emitted their tweets by means of air forced through small organ-like pipes, and anyone who has heard the bird sounds in Haydn's Toy Symphony will know that this simple means of sound production can give remarkably realistic results. But perhaps the most important aspect of the multiple bird automaton is that it laid down a sequence in which the birds would sing, and so it stands as one of the very earliest precursors of what we know nowadays as mechanical music. Heron from Alexandria (Heron Alexandrinus) was a Mathematician, Physicist and Engineer who lived in 10-70 AD but some references consider also 150 AD which is probably wrong, as in one of his works he referred to a recent eclipse which is now thought to have occurred in 13 March 62 AD. The water-organ (Hydraulis) is described in detail in Book 1, Chapter 42 of the Pneumatika by Hero of Alexandria. He lived in the latter part of the first century AD in Alexandria, a century or more after the period of the Ptolemies, but apparently had access to the works of Ktesibios (Ctesibius), who is generally believed to have been the original inventor. Ctesibius created the hydraulis when he connected a set of pipes to a source of wind via a key mechanism. The term hydraulis derives from the mechanism that harnesses water pressure to produce the wind that enters the pipes. A pump handle operates a plunger that forces air from iwithin a cylinder into a confuit leading to a funnel-shaped air container. This container, or ‘pigneus’, is open at both top and bottom and is placed neck upward on blocks in a water cistern. The pressure of the incoming air displaces some of the water in the cistern, and as the plunger is depressed to prepare for the next stroke, the weight of the water pushes the air into the windchest of the organ. The pipes stand above the windchest; they receive air through a system of perforated sliders, controlled by keys that are depressed by the organist. (Kimberley Marshall. Compiled from various sources)
‣ Source : Bush, Earl and Kassel, Richard (2006), “The Organ : An Encyclopedia”, Routledge, pp.266.
‣ Source : Hawkins, Sir John (1853), “A General History of the Science and Practice of Music”, London : J. Alfred Novello, Chapter XV, pp. 70-72.
‣ Source : Vitruvius (Marcus Vitruvius Pollio) (ca - 25 BC), “De Architectura, libri decem”, Book V, Chap. IX, lib. VIII, “De Hydraulicis”, Transcribed by Valentin Rose, published by Teubner (1867)
‣ Urls : http://www.history.rochester.edu/steam/hero/index.html (last visited ) http://www.mlahanas.de/Greeks/HeronAlexandria.htm (last visited ) http://penelope.uchicago.edu/Thayer/E/Roman/Texts/Vitruvius/9*.html (last visited ) http://www.youtube.com/watch?v=atT7Tjpn5js (last visited )
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