University of Groningen

The Pulse of Time: Galileo Galilei, the Determination of Longitude, and the Pendulum Clock. Silvio A. Bedini North, J. D.

Published in: Isis

DOI: 10.1086/356235

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Publication date: 1992

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Citation for published version (APA): North, J. D. (1992). The Pulse of Time: Galileo Galilei, the Determination of Longitude, and the Pendulum Clock. Silvio A. Bedini. Isis, 83(3), 491-492. https://doi.org/10.1086/356235

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Review Reviewed Work(s): The Pulse of Time: Galileo Galilei, the Determination of Longitude, and the Pendulum Clock by Silvio A. Bedini Review by: J. D. North Source: Isis, Vol. 83, No. 3 (Sep., 1992), pp. 491-492 Published by: The University of Chicago Press on behalf of The History of Science Society Stable URL: https://www.jstor.org/stable/233936 Accessed: 10-12-2018 15:29 UTC

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This content downloaded from 129.125.148.19 on Mon, 10 Dec 2018 15:29:51 UTC All use subject to https://about.jstor.org/terms BOOK REVIEWS-ISIS, 83: 3 (1992) 491 opinion adequately justified the central the- tude at sea, but that was one of the most sis of his book. powerful incentives to Galileo. His first In this first generation of scientists imme- conception of a workable scheme dates diately after Galileo, astronomy obviously from 1641-1642; it was the basis of a work- was to receive little attention. Their inter- ing device within a decade or so, in Flor- ests turned rather to geometry and physics, ence. In 1656 or 1657, Christiaan Huygens and specifically to the problems of indivisi- devised and put into execution an alterna- bles and the composition of the continuum, tive solution. National pride over the prior- problems that were beyond the tools avail- ity question still keeps the flame of contro- able at the time. Segre argues, contrary to versy flickering faintly, but Silvio Bedini Pietro Redondi, that the evidence shows shows that he is capable of taking a reason- that religion was not the cause of the im- ably distanced view of events and of con- passe reached by these scientists; rather, centrating on the finer points of this very the difficulty was the intrinsic recalcitrance rich area of study. of the problems themselves. The idea of a portable timepiece to en- Segre's other main goal is to demytholo- able the measurement of longitude at sea gize the picture of Galileo in the secondary was clearly expressed by Gemma Frisius in literature. The hagiographic image is traced 1522. Various others had the same idea, back to Viviani's biography, which is and watches seem even to have been in use shown by close textual study to reveal at for this purpose-perhaps not effectively- least as much about biographical standards before the end of the sixteenth century. of that age as it does about Galileo's life The pendulum clock is not, as we can see, and work. Likewise, a lengthy discussion particularly well fitted to time measurement of the twentieth-century dispute over at sea, and although it owed its existence to whether Galileo was more of an empiricist the longitude problem, one can usefully dis- or an "a priorist" in his methodology (the tinguish between motivation and inspiration former attribution is traced to Viviani, here. Similarities between the pendulum while the latter seems to be closer to and its predecessors are fairly obvious, to Segre's reading of Galileo) concludes that those who have the advantage of hindsight. this dispute anachronistically tells us more Galileo does not-of course-reveal his about contemporary philosophies of sci- sources of inspiration. His biographer Vin- ence than it does about patterns of thought cenzio Viviani, as we all know, claimed appropriate to the age of Galileo. Support- that the idea came from Galileo's watching ing this is Segre's interesting finding that a lamp in the cathedral of Pisa. Bedini turns Galileo's followers are just as ambiguous as our attention rather toward Galileo's exper- he is on methodological issues. iments in music and his well-known use of a This book has some important new things pendulum (pulsilogium) to determine the to add, and thus is a welcome complement pulse rates of patients with fever. The orig- to the already huge literature on the Galileo inality of Galileo's device, even the discov- case. ery of the isochronism of the pendulum, RICHARD J. BLACKWELL was subject to dispute almost at once, and that he kept the tune in a very low key sug- gests that he could see the justice of some of the points being made by his detractors. Just as inevitably, the tempo quickened Silvio A. Bedini. The Pulse of Time: Galileo when rich research contracts with foreign Galilei, the Determination of Longitude, princes were in the wind. His negotiations and the Pendulum Clock. (Biblioteca di with the Spaniards and the States General, Nuncius, Studi e Testi, 3.) xiv + 132 pp., not to mention some of the details of his frontis., illus., apps., index. Florence: Leo inventions, make salutary reading. I like in S. Olschki, 1991. L 40,000 (paper). particular the headgear with telescope at- The pendulum as a regulator for timekeep- tached, leaving one eye free. ing represents by any standards an impor- Galileo's clockwork devices were the tant stage in the development of precision product of the end of his life, and blindness in the empirical sciences, pure and applied. meant that he had to collaborate with his One cannot say that it would never have son, and not only on practical problems. been conceived outside the context of the Here is one of the chief causes of the ob- search for reliable methods of finding longi- fuscation of history; another is the obvious

This content downloaded from 129.125.148.19 on Mon, 10 Dec 2018 15:29:51 UTC All use subject to https://about.jstor.org/terms 492 BOOK REVIEWS-ISIS, 83: 3 (1992)

chapters, however, concerns a little-known but important fact: the great public clock of the Palazzo Vecchio in Florence, embody- ing Galileo's two clockwork inventions (the escapement and the pendulum regulator), by means of which the grand duke planned to standardize time reckoning throughout L K Tuscany, continues to work without major modification to the present day. In all this, R we should not overlook the important part N H played by the much maligned Viviani, court mathematician and supervisor of the Tus- can project. It is ironic that much of what we know of the earliest history of the clock in the Palazzo Vecchio comes from a draw- ing that Prince Leopold sent to Ismael Boulliau in 1659 to be forwarded to Huy- gens. The drawing is still in the Huygens papers at Leiden. Bedini gives much useful information, not only about the pendulum clocks he dis- cusses, but about their medieval forebears. He includes some excellent illustrations, chapters on Viviani's tables for the stan- dardization of time, and a brief but invalu- able survey of the manuscripts relevant to the entire historical episode. Much has been written on this over the centuries, but Bedini's now becomes the most important self-contained account. J. D. NORTH

A. Arnauld. On True and False Ideas. Translated, with an introductory essay by Stephen Gaukroger. (Classics of Philosophy and Science.) viii + 240 pp., illus., bibl., index. Manchester/New York: Manchester University Press, 1990. $59.95.

Antoine Arnauld's Traite des vrais and fausses idees (1683) opened an angry dis- Schematic drawing of the pendulum-regulated pute with Nicole Malebranche on the na- clock designed by Christiaan Huygens ture of ideas and their function in percep- (reprinted in Bedini, Pulse of Time from tual cognition that, merged with the Huygens, Horologium). question of grace, lasted up to Arnauld's death in 1694. Stephen Gaukroger offers to need to keep secrecy on a matter with great the English-speaking world a first and accu- financial advantages. Bedini tells the story rate version of this important work. In the of the clock, and of subsequent contro- introductory essay, the editor proficiently versy, with verve and simple honesty. He describes the philosophical and scientific makes useful comparisons with the work of framework within which the debacle of Ar- Huygens and goes in some detail into a istotelianism and the ambiguities in Des- number of clocks in the Medici collections. cartes's account of perception raised the is- (Not least among them was the dragon sue of ideas in the second half of the clock that Cosimo II presented to the em- seventeenth century. Among the causes of peror of China.) One of the most enjoyable the downfall of the Aristotelian explanation

This content downloaded from 129.125.148.19 on Mon, 10 Dec 2018 15:29:51 UTC All use subject to https://about.jstor.org/terms