Part 7

CHINA

1074 Shen Kua, clocks and magnetic compass 1080 Su Sung clock built 1101 Su Sung clock destroyed

INDIA

1100 (ca.) Sūrya Siddhānta animated astronomical models and perpetual motion 1150 (ca.) Siddhānta Siromaṇi animated models and perpetual motion

ISLAM

1150 Saladin clock

EUROPE

1187 Neckham on compass 1198 Jocelin on water clock

ISLAM

1200 (ca.) Riḍwān water-clocks, perpetual motion and weight drive 1206 al-Jazarī clocks, etc. 1221 Geared astrolabe 1232 Charlemagne clock 1243 al-Konbas (compass)

EUROPE

1245 Villard clocktower, "escapement," perpetual motion 1267 Villers Abbey clock 1269 Peregrinus, compass and perpetual motion 1271 Robertus Anglicus, animated models and "perpetual motion" clock

ISLAM

1272 Alfonsine corpus clock with mercury drum, equatoria

EUROPE

1285 Drover's water clock with wheel and weight drive 1300 (ca.) French geared astrolabe 1320 Richard of Wallingford astronomical clock and equatorium 1364 de Dondi's astronomical clock with mechanical escapement later 14th C. Tradition of escapement clocks continues and degenerates into simple time-keepers ------------------------------------------------------------------------

There is therefore reasonable grounds for supporting the medieval European tradition that the magnetic compass had first come from China, though one cannot well admit that the first news of it was brought, as the legend states, by Marco Polo, when he returned home in 1260. There might well have been another wave of interest, giving the impetus to Peter Peregrinus at this time, but an earlier transmission, perhaps along the silk road or by travelers in crusades, must be postulated to account for the evidence in Europe, ca. 1200. The earlier influx does not play any great part in our main story; it arrived in Europe before the transmission of astronomy from Islam had got under way sufficiently to make protoclocks a subject of interest. For a second transmission, we have already seen how the relevant texts seem to cluster, in France ca. 1270, around a complex in which the protoclocks seem combined with the ideas of perpetual motion wheels and with new information about the magnetic compass.

The point of this paper is that such a complex exists, cutting across the histories of the clock, the various types of astronomical machines, and the magnetic compass, and including the origin of "self-moving wheels." It seems to trace a path extending from China, through India and through Eastern and Western Islam, ending in Europe in the Middle Ages. This path is not a simple one, for the various elements make their appearances in different combinations from place to place, sometimes one may be dominant, sometimes another may be absent. Only by treating it as a whole has it been possible to produce the threads of continuity which will, I hope, make further research possible, circumventing the blind alleys found in the past and leading eventually to a complete understanding of the first complicated scientific machines.

FOOTNOTES:

This traditional view is expressed by almost every history of horology. An ultimate source for many of these has been the following two classic treatments: J. Beckmann, A history of inventions and discoveries, 4th ed., London, 1846, vol. 1, pp. 340 ff. A. P. Usher, A history of mechanical inventions, 2nd ed., Harvard University Press. 1954, pp. 191 ff., 304 ff.

There is a considerable literature dealing with the later evolution of perpetual motion devices. The most comprehensive treatment is H. Dircks, Perpetuum mobile, London, 1861; 2nd ser., London, 1870. So far as I know there has not previously been much discussion of the history of such devices before the renaissance.

For the early history of gearing in the West see C. Matschoss, Geschichte des Zahnrades, Berlin, 1940. Also F. M. Feldhaus, Die geschichtliche Entwicklung des Zahnrades in Theorie und Praxis, Berlin, 1911.

A general account of these important archaeological objects will be published by J. Needham, Science and civilisation in China, Cambridge, 1959(?), vol. 4. The original publications (in Chinese) are as follows: Wang Chen-to, "Investigations and reproduction in model form of the south-pointing carriage and hodometer," National Peiping Academy Historical Journal, 1937, vol. 3, p. 1. Liu Hsien-chou, "Chinese inventions in horological engineering," Ch'ing-Hua University Engineering Journal, 1956, vol. 4, p. 1.

For illustrations of intermeshing worms in Indian cotton mills, see Matschoss, op. cit. (footnote 3), figs. 5, 6, 7, p. 7.

It is interesting to note that the Chinese hodometer was contemporary with that of Hero and Vitruvius and very similar in design. There is no evidence whatsoever upon which to decide whether there may have been a specific transmission of this invention or even a "stimulus diffusion."

A summary of the content of the manuscript sources, illustrated by the original drawings, has been published by H. Alan Lloyd, Giovanni de Dondi's horological masterpiece, 1364, without date or imprint (?Lausanne, 1955), 23 pp. It should be remarked that de Dondi declines to describe the workings of his crown and foliot escapement (though it is well illustrated) saying that this is of the "common" variety and if the reader does not understand such simple things he need not hope to comprehend the complexities of this mighty clock. But this may be bravado to quite a large degree.

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.

Derek J. Price, "Clockwork before the clock," Horological Journal, 1955, vol. 97, p. 810, and 1956, vol. 98, p. 31.