Part 5

[8] See, for example, the chronological tables of the 14th century and the later mentions of clocks in E. Zinner, _Aus der Frühzeit der Räderuhr_, Munich, 1954, p. 29 ff. Unfortunately this very complete treatment tends to confuse the factual and legendary sources prior to the clock of de Dondi; it also accepts the very doubtful evidence of the "escapement" drawn by Villard of Honnecourt (see p. 107). An excellent and fully illustrated account of monumental astronomical clocks throughout the world is given by Alfred Ungerer, _Les horloges astronomiques_, Strasbourg, 1931, 514 pp. Available accounts of the development of the planetarium since the middle ages are very brief and especially weak on the early history: Helmut Werner, _From the Aratus globe to the Zeiss planetarium_, Stuttgart, 1957; C. A. Crommelin, "Planetaria, a historical survey," _Antiquarian Horology_, 1955, vol. 1, pp. 70-75.

[9] Derek J. Price, "Clockwork before the clock," _Horological Journal_, 1955, vol. 97, p. 810, and 1956, vol. 98, p. 31.

[10] For the use of this material I am indebted to my co-authors. I must also acknowledge thanks to the Cambridge University Press, which in the near future will be publishing our monograph, "Heavenly Clockwork." Some of the findings of this paper are included in shorter form as background material for that monograph. A brief account of the discovery of this material has been published by J. Needham, Wang Ling, and Derek J. Price, "Chinese astronomical clockwork," _Nature_, 1956, vol. 177, pp. 600-602.

[11] For these translations from classical authors I am indebted to Professor Loren MacKinney and Miss Harriet Lattin, who had collected them for a history, now abandoned, of planetariums. I am grateful for the opportunity of giving them here the mention they deserve.

[12] A. G. Drachmann, "The plane astrolabe and the anaphoric clock," _Centaurus_, 1954, vol. 3, pp. 183-189.

[13] A fuller description of the anaphoric clock and cognate water-clocks is given by A. G. Drachmann, "Ktesibios, Philon and Heron," _Acta Historica Scientiarum Naturalium et Medicinalium_, Copenhagen, 1948, vol. 4.

[14] First published by O. Benndorf, E. Weiss, and A. Rehm, _Jahreshefte des österreichischen archäologischen Institut in Wien_, 1903, vol. 6, pp. 32-49. I have given further details of its construction in _A history of technology_, ed. Singer, Holmyard, and Hall, 1957, vol. 3, pp. 604-605.

[15] L. Maxe-Werly, _Mémoires de la Société Nationale des Antiquaires de France_, 1887, vol. 48, pp. 170-178.

[16] The first definitive account of the Antikythera machine was given by Perikles Rediadis in J. Svoronos, _Das Athener Nationalmuseum_, Athens, 1908, Textband I, pp. 43-51. Since then, other photographs (mostly very poor) have appeared, and an attempt at a reconstruction has been made by Rear Admiral Jean Theophanidis, _Praktika tes Akademias Athenon_, Athens, 1934, vol. 9, pp. 140-149 (in French). I am deeply grateful to the Director of the Athens National Museum, M. Karouzos, for providing me with an excellent new set of photos, from which figures 6-8 are now taken.

[17] H. Diels Über die von Prokop beschriebene Kunstuhr von Gaza, _Abhandlungen, Akademie der Wissenschaften_, Berlin, Philos.-Hist. Klasse, 1917, No. 7.

[18] L. A. Mayer, _Islamic astrolabists and their works_, Geneva, 1956, p. 62.

[19] The translation which follows is quoted from J. Beckmann, _op. cit._ (footnote 1), p. 349.

[20] E. Wiedemann, "Ein Instrument das die Bewegung von Sonne und Mond darstellt, nach al Biruni," _Der Islam_, 1913, vol. 4, p. 5.

[21] I acknowledge with thanks to the Curator of that museum the permission to reproduce photographs of this instrument. It is item 5 in R. T. Gunther, _Astrolabes of the world_, Oxford, 1932.

[22] Abulcacim Abnacahm, _Libros del saber_, edition by Rico y Sinobas, Madrid, 1866, vol. 3, pp. 241-271. The design of the instrument has been very fully discussed by A. Wegener, "Die astronomischen Werke Alfons X," _Bibliotheca Mathematica_, 1905, pp. 129-189. A more complete discussion of the historical evolution of the equatorium is given in Derek J. Price, _The equatorie of the planetis_, Cambridge (Eng.), 1955, pp. 119-133.

[23] E. Wiedemann, and F. Hauser, "Über die Uhren im Bereich d. islamischen Kultur," _Nova Acta; Abhandlungen der königliche Leopoldinisch-Carolinische Deutsche Akademie der Naturforscher zu Halle_, 1915, vol. 100, no. 5.

[24] E. Wiedemann, and F. Hauser, _Die Uhr des Archimedes und zwei andere Vorrichtungen_, Halle, 1918.

[25] The manuscripts in question are as follows: Gotha, Kat. v. Pertsch. 3, 18, no. 1348; Oxford, Cod. 954; Leiden, Kat. 3, 288, no. 1414, Cod. 499 Warn; and another similar, Kat. 3, 291, no. 1415, Cod. 93 Gol.

[26] H. Schmeller, Beiträge zur Geschichte der Technik in der Antike und bei den Arabern, Erlangen, 1922 (_Abhandlungen zur Geschichte der Naturwissenschaften und der Medizin_ no. 6).

[27] Once more I am indebted to Professor Loren MacKinney and Miss Harriet Lattin (see footnote 11) for making their collections on Gerbert available to me.

[28] Item 198 in Gunther, _op. cit._ (footnote 21). I am grateful to the authorities of that museum for permission to reproduce photographs of this instrument.

[29] Sotheby and Co., London, sale of March 14, 1957, lot 154. The outer rim of the rete has 120 teeth.

[30] The Latin text of the treatise on the Albion, has been transcribed by Rev. H. Salter and published in R. T. Gunther, _Early science in Oxford_, Oxford, 1923, vol. 2, pp. 349-370. An analysis of its design is given in Price, _op. cit._ (footnote 22), pp. 127-130.

[31] Such evidence as there is for the existence and form of the clock is collected by Gunther, _op. cit._ (footnote 30), p. 49.

[32] I have discussed this new manuscript source in "Two medieval texts on astronomical clocks," _Antiquarian Horology_, 1956, vol. 1, no. 10, p. 156. The manuscript in question is ms. 230/116, Gonville and Caius College, Cambridge, folios 11ᵛ-14ᵛ = pp. 31-36.

[33] _The Chronicle of Jocelin of Brakelond_ ..., H. E. Butler (ed.), London, 1949, p. 106.

[34] C. B. Drover, "A medieval monastic water-clock," _Antiquarian Horology_, 1954, vol. 1, no. 5, pp. 54-58, 63. Because this water clock uses wheels and strikes bells one must reject the evidence of literary reference, such as by Dante, from which the mention of wheels and bells have been taken as positive proof of the existence of mechanical clocks with mechanical escapements. The to-and-fro motion of the mechanical clock escapement is quite an impressive feature, but there seems to be no literary reference to it before the time of de Dondi.

[35] _Annales de la Société Royale d'Archéologie de Bruxelles_, 1896, vol. 1/8, pp. 203-215, 404-451. The translation here is cited from Drover, _op. cit._, (footnote 34), p. 56.

[36] L. Thorndike, _The sphere of Sacrobosco and its commentators_, Chicago, 1949, pp. 180, 230.

[37] The album was published with facsimiles by J. B. A. Lassus, 1858. An English edition with facsimiles of 33 of the 41 folios was published by Rev. Robert Willis, Oxford, 1859. An extensive summary of this section is given, with illustrations, by J. Drummond Robertson, _The evolution of clockwork_, London, 1931, pp. 11-15.

[38] M. Jules Quicherat, _Revue Archèologique_, 1849, vol. 6.

[39] M. C. Frémont. _Origine de l'horloge à poids_, Paris, 1915.

[40] For this, I have used and quoted from the very beautiful edition in English, prepared by Silvanus P. Thompson, London, Chiswick Press, 1902.

[41] See E. G. R. Taylor, "The South-pointing needle," _Imago Mundi_, Leiden, 1951, vol. 8, pp. 1-7 (especially pp. 1, 2).

[42] I have wondered whether the medieval interest in perpetual motion could be connected with the use of the "Wheel of Fortune" in churches as a substitute for bell-ringing on Good Friday. Unfortunately I can find no evidence for or against the conjecture.

[43] W. E. May, "Alexander Neckham and the pivoted compass needle," _Journal of the Institute of Navigation_, 1955, vol. 8, no. 3, pp. 283-284.

[44] W. E. May, "Hugues de Berze and the mariner's compass," _The Mariner's Mirror_, 1953, vol. 39, no. 2, pp. 103-106.

[45] H. Balmer, _Beiträge zur Geschichte der Erkenntnis des Erdmagnetismus_, Aarau, 1956, p. 52.

[46] The collection is the _Gami 'al Hikajat_; the relevant passage being given in German translation in Balmer. _op. cit._ (footnote 45), p. 54.

[47] Balmer, op. _cit._ (footnote 45), p. 53.

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