Jian-Liang Lin; Hong-Sen Yan. Decoding the Mechanisms of Antikythera Astronomical Device. x + 281 pp., figs., bibls., apps., index. Heidelberg: Springer, 2016. $109 (cloth).

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Previous articleNext article FreeJian-Liang Lin; Hong-Sen Yan. Decoding the Mechanisms of Antikythera Astronomical Device. x + 281 pp., figs., bibls., apps., index. Heidelberg: Springer, 2016. $109 (cloth).Efthymios NicolaidisEfthymios Nicolaidis Search for more articles by this author PDFPDF PLUSFull Text Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinked InRedditEmailQR Code SectionsMoreThe Antikythera mechanism is the scientific instrument of antiquity that has been most discussed among historians of science and technology. Made circa 100 b.c. and discovered in 1901 in a shipwreck near Antikythera Island, Greece, it has now been studied for more than a century. In 2005 an international multidisciplinary team was formed and x-ray 3D imaging plus special surface photography was performed. The study of the mechanism can be divided in two sections: the mechanical parts and the inscriptions. In June 2016 the research team presented its findings on the inscriptions, as they have been read using scanning and surface photography technologies, in a special 320-page issue of the journal Almagest (7[1]).The up-to-date results of the research team indicate that the Antikythera mechanism is a geared device, measuring about 30 × 20 × 10 cm, that computes astronomical measurements and calendrical determinations. At the front, a dial shows the places of the Sun, the Moon, and the other five planets of the ancients on the zodiac at a day chosen by the user. At the back, two spiral dials compute the lunisolar calendar (Metonic and Callippic cycles) and the eclipses following the Saros and Exeligmos cycles. Inscriptions are to be found on two metal plates closing the front and rear faces of the wooden case of the mechanism and also on the front and back dials. Owing to the poor condition of the recovered mechanism (eighty-two fragments preserving about a third of the device), we have evidence only for its computation of the motion of the Moon and the Sun and calendrical gearing. Nevertheless, the likelihood that the mechanism had planetary gearing is strongly supported by the recent results of work on the inscriptions: the names of planets and mathematics applicable to planetary motions have been deciphered.Decoding the Mechanisms of Antikythera Astronomical Device is the outcome of a collaboration between a specialist in ancient astronomical instruments (Jian-Liang Lin) and a specialist in machine design and the reconstruction of ancient machinery (Hong-Sen Yan). The aim of the book is to offer an overview of the research on the gearing system of the mechanism by presenting and comparing the models for its reconstruction. It also presents the proposals of the authors following a specific reconstruction design methodology developed in a special chapter (Ch. 5). The authors claim that their methodology defines relevant problems, identifies appropriate structural characteristics and reconstructs all feasible mechanisms for the reconstruction designs of lost ancient mechanisms. “The methodology for the reconstruction designs of lost ancient mechanisms is developed based on the methodology for the creative designs of modern mechanisms. It includes four steps: design specifications, generalized chains, specialized chains, and reconstruction designs” (p. 88).After the discovery by Michael Wright of the pin-in-slot joint of the Antikythera mechanism that models the eccentric cycle of the lunar motion (M. T. Wright, “The Antikythera Mechanism and the Early History of the Moon-Phase Display,” Antiquarian Horology, 2006, 29:319–329), and after the 3D representations of the interior of the fragments by the scans of 2005, specialists have no fundamental disagreements about lunar motion gearing. The Sun is posing more serious problems, as a great part of its gearing mechanism is missing. Lin and Yan propose four different possible designs, including one that uses a pin-in-slot joint.The major problem for the reconstruction of the mechanism pertains to the planetary motions, since no evidence is left of their gearing among the recovered fragments of the mechanism. Such a reconstruction has to deal with the following problems: the mechanism is unique (no other has yet been found); the written testimonies attesting to the existence of such mechanisms do not describe them (about fifty are identified by Mike G. Edmunds, “The Antikythera Mechanism and the Mechanical Universe,” Contemporary Physics, 2014, 55:263–285); and other findings pertaining to Greek gearing tradition are in comparison extremely basic (J. V. Field and M. T. Wright, “Gears from the Byzantines: A Portable Sundial with Calendrical Gearing,” Annals of Science, 1985, 42:87–138). Therefore, the hypothetical planetary gearing reconstructions offered are based on the surviving solar and lunar gearing and on the assumption that the planetary motions follow Hipparchus’s planetary theory. The authors’ reconstructions are based on a contemporary mathematical model: what possible gearing devices can represent planetary motions? In the appendix Lin and Yan give “all 48 feasible designs of complete interior mechanisms” of the Antikythera mechanism.Such a methodology does not take the historical context into sufficient account. In addition to the problems posed by our poor knowledge of Hipparchus’s planetary knowledge and the overall mathematical background of the second–first centuries b.c., one must take into account the construction problems. The 3D computer models assist in the visualization and the reconstruction design of ancient mechanisms, but only a real reconstruction—with materials, technologies, and methods available during the second century b.c.—can prove the workability of a proposed model. Indeed, the complex gearing system (about fifty gears) does not allow all reconstructions to function; without actually making the reconstruction experiments, we cannot be sure whether the models will really work. Notes Efthymios Nicolaidis is Director of Research at the National Hellenic Research Foundation, Greece. His publications focus on the history of science in the Greek world (Byzantine and modern periods), the history of astronomy, and science and religion. He is now President of the Division of History of Science and Technology of the International Union of History and Philosophy of Science and Technology. Previous articleNext article DetailsFiguresReferencesCited by Isis Volume 108, Number 1March 2017 Publication of the History of Science Society Article DOIhttps://doi.org/10.1086/691324 © 2017 by The History of Science Society. All rights reserved.PDF download Crossref reports no articles citing this article.