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John Flamsteed and the turn of the screw: mechanical uncertainty, the skilful astronomer and the burden of seeing correctly at the Royal Observatory, Greenwich

Published online by Cambridge University Press:  05 March 2014

McGill University, Leacock, Rm 632, Department of History, 855 Sherbrooke West, Montreal, Quebec, H3A 2T7, Canada. Email:


Centring on John Flamsteed (1646–1719), the first Astronomer Royal, this paper investigates the ways in which astronomers of the late seventeenth century worked to build and maintain their reputations by demonstrating, for their peers and for posterity, their proficiency in managing visual technologies. By looking at his correspondence and by offering a graphic and textual analysis of the preface to his posthumous Historia Coelestis Britannica (1725), I argue that Flamsteed based the legitimacy of his life's work on his capacity to serve as a skilful astronomer who could coordinate the production and proper use of astronomical sighting instruments. Technological advances in astrometry were, for Flamsteed, a necessary but not a sufficient condition for the advancement of astronomy. Technological resources needed to be used by the right person. The work of the skilful astronomer was a necessary precondition for the mobilization and proper management of astronomical technologies. Flamsteed's understanding of the astronomer as a skilled actor importantly shifted the emphasis in precision astronomical work away from the individual observer's ability to see well and toward the astronomer's ability to ensure that instruments guaranteed accurate vision.

Research Article
Copyright © British Society for the History of Science 2014 

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1 Forbes, Eric (ed.), The Gresham Lectures of John Flamsteed, London: Mansell, 1975, p. 147Google Scholar.

2 Flamsteed was likely trying to save face with these comments as this lecture followed a quarrel that took place between Flamsteed and Robert Hooke at Garraway's coffee house in which Flamsteed left the coffee house humiliated. Flamsteed used the opening remarks of this lecture to set himself apart not only from Hooke but also from Hevelius and Riccioli, all of whom he considered exemplars of poor astronomical work. See Forbes, op. cit. (1), pp. 147, 149, 160 n. 6.7; Johns, Adrian, The Nature of the Book: Print Knowledge in the Making, Chicago: The University of Chicago Press, 1998, pp. 554555CrossRefGoogle Scholar; Johns, , ‘Flamsteed's optics and the identity of the astronomical observer’, in Willmoth, Frances (eds.), Flamsteed's Stars: New Perspectives on the Life and Work of the First Astronomer Royal (1646–1719), Woodbridge: Boydell Press in association with the National Maritime Museum, 1997Google Scholar, 77–106, 81–90.

3 The clearest iterations of this are seen in Chapman, Allan (ed.), The Preface to John Flamsteed's Historia Coelestis Britannica (1725), London: Trustees of the National Maritime Museum, 1982, p. 1Google Scholar; Chapman, , Dividing the Circle: The Development of Critical Angular Measurement in Astronomy, 1500–1850, Chichester: John Wiley & Sons, 1995, pp. 3435, 49–59Google Scholar.

4 Johns's work is a notable exception. See Johns, ‘Flamsteed's optics’, op. cit. (2).

5 On the example of Kepler and Galileo see van Helden, Albert, ‘Telescopes and authority from Galileo to Cassini’, Osiris (1994) 9, pp. 829, 11–13Google Scholar.

6 According to Chapman, it was through improved instruments and methods of mathematical reduction that Flamsteed thought astronomical knowledge could be improved. By comparison, I argue that, for Flamsteed, a particular type of person with particular skills needed to put instruments and methods to work in order to genuinely advance astronomical knowledge. Chapman, The Preface, op. cit. (3), p. 1; Chapman, Dividing the Circle, op. cit. (3), pp. 34–35, 49–59.

7 Buchwald, Jed Z., ‘Discrepant measurements and experimental knowledge in the early modern era,’ Archive for the History of Exact Sciences (2006) 60, pp. 565649Google Scholar, 590 (emphasis added).

8 Queen Anne's Warrant Appointing Visitors to the Royal Observatory, 12 December 1710, in Eric Forbes, Murdin, Lesley and Willmoth, Frances (eds.), The Correspondence of John Flamsteed, the First Astronomer Royal (hereafter CJF), 3 vols., Bristol: Institute of Physics Publishing, 1995, vol. 1Google Scholar; Baily, Francis (ed.), An Account of the Revd. John Flamsteed, the First Astronomer-Royal: Compiled from His Own Manuscripts, and Other Authentic Documents, Never before Published & Supplement to the Account of the Revd. John Flamsteed, London: Dawson, 1966, p. 91Google Scholar.

9 Derham, William, The Artifical Clockmaker: A Treatise of Watch and Clockwork, 2nd edn, London, 1700Google Scholar.

10 The directions on how to build a telescope only appear in an appendix in the second edition of the book. The first edition of Derham's volume was published in 1696.

11 Derham, op. cit. (9).

12 Derham, op. cit. (9).

13 I owe the wording of this sentence to Voula Saridakis, who writes, ‘the development of the telescope dominated much of the seventeenth century, yet it was the invention and ultimate implementation of micrometers and telescopic sights that turned astronomy from a field of discovery into one of measurement’. See Voula Saridakis, ‘Converging elements in the development of late seventeenth-century disciplinary astronomy: instrumentation, education, networks, and the Hevelius–Hooke controversy’, PhD dissertation, Virginia Institute of Technology, 2001, OCLC 48543806, p. 10. Although not perfectly distinct, the difference between describing and measuring in astronomy is often tied to the kind of astronomical problems the astronomer is trying to solve. See Schaffer, Simon, ‘Herschel in Bedlam: natural history and stellar astronomy’, BJHS (1980) 13, pp. 211239Google Scholar.

14 Derham himself was in direct contact with Flamsteed, and on at least one occasion visited the Royal Observatory. He received explicit instructions from the Astronomer Royal on how to conduct his micrometer, which Derham refered to as ‘Flamsteedian’ in design. See Derham to Flamsteed, 15 October 1706, CJF, vol. 3; Derham to Flamsteed, 29 October 1706, CJF, vol. 3.

15 Gregory to Flamsteed, 19 July 1673, CJF, vol. 1.

16 Flamsteed to Cassini, 7 July 1673, CJF, vol. 1; Flamsteed, John, ‘Johannis Flamstedi … Novas Observationes …’, Philosophical Transactions (1673) 8, pp. 60946100Google Scholar.

17 Micrometers were typically graduated by determining how many parts an inch could be divided into. Normally, this was done by counting how many revolutions of the screw were required to create the space of an inch between the dividers of the instrument. Degrees of arc where then determined trigonometrically. Flamsteed to Cassini, 7 July 1673, CJF, vol. 1.

18 Later in his career Flamsteed held that the micrometer even created the possibility of measuring stellar parallax. Johns, ‘Flamsteed's optics’, op. cit. (2), pp. 93–100, 104–106, describes the lengths Flamsteed went to to convince his community that he was actually observing stellar parallax; also see Williams, M.E.W., ‘Flamsteed's alleged measurement of annual parallax for the Pole Star’, Journal for the History of Astronomy (1979) 10, pp. 102116CrossRefGoogle Scholar.

19 Gregory to Flamsteed, 19 July 1673, CJF, vol. 1; Flamsteed to Gregory, 2 August 1673, CJF, vol. 1.

20 Flamsteed to Gregory, 2 August 1673, CJF, vol. 1.

21 Following Mario Biagioli, the approach outlined here centres on geographical distance and time as factors that limit access to information and on how these factors serve as a function of identity construction in an economy of social and epistemic legitimacy. On this and as a useful comparison to the present study see Biagioli, Mario, Galileo's Instruments of Credit: Telescopes, Instruments, Secrecy, Chicago: The University of Chicago Press, 2006Google Scholar, Chapter 1; Forbes, op. cit. (1), p. 147.

22 On the invention and early dissemination of micrometers see Brooks, Randall C., ‘The development of micrometers in the seventeenth, eighteenth and nineteenth centuries’, Journal for the History of Astronomy (1991) 22, pp. 127173, 129–130Google Scholar; Brooks, , ‘Origins, usage and production of screws: an historical perspective’, History and Technology (1991) 8, pp. 5176, 57Google Scholar; Chapman, Dividing the Circle, op. cit. (3), pp. 35–45; Saridakis, op. cit. (13), pp. 36–40; Bennett, Jim, The Divided Circle: A History of Instruments for Astronomy, Navigation, and Surveying, Oxford: Phaidon, 1987Google Scholar; McKeon, R.M., ‘Les débuts de l'astronomie de précision: I. Histoire de la réalisation du micromètre astronomique’, Physis (1971) 13, pp. 225288Google Scholar.

23 Auzout to Oldenburg, 18 December 1666, in Hall, A.R. and Hall, M.B. (eds.), The Correspondences of Henry Oldenburg (hereafter CHO), 13 vols., Madison: University of Wisconsin Press, 1965–1986, vol. 3Google Scholar; [Adrian] Auzout, ‘An Extract of a Letter … by Auzout, M.… Concerning a Way of his, for Taking the Diameters of the Planets …’, Philosophical Transactions (1665) 1, pp. 373375Google Scholar.

24 Towneley, Richard, ‘An Extract of a Letter … Touching the Invention of Dividing a Foot into Many Thousand Parts …’, Philosophical Transactions (1666–1667) 2, pp. 457458Google Scholar.

25 In his original letter to Cassini and in the published version in the Philosophical Transactions, Flamsteed recorded that ‘a single foot is divided into 3507 parts’ (emphasis added). The unit of feet in this passage is almost certainly a typographical error. When Flamsteed wrote to Moore about the calibration of his micrometer nearly a year after he wrote to Cassini (see below), he reported that he could divide a single inch into 3507 parts. Flamsteed to Cassini, 7 July 1673, CJF, vol. 1; Flamsteed to Moore, April 1674, CJF, vol. 1.

26 Brooks, ‘The development of micrometers’, op. cit. (22), pp. 132–135.

27 Hevelius to Oldenburg, 19 November 1668, CHO, vol. 5.

28 See below.

29 Flamsteed recalled in two different accounts of his life and work that the micrometer was an important part of his rise as an astronomer. See Baily, op. cit. (8), pp. 28–29; Chapman, The Preface, op. cit. (3), p. 113.

30 Flamsteed to Collins, 19 September 1670, CJF, vol. 1.

31 Willmoth, Frances, Sir Jonas Moore: Practical Mathematics and Restoration Science, Woodbridge: The Boydell Press, 1993, p. 166Google Scholar. Willmoth also discusses the significance that the influence of the so-called ‘northern astronomers’ made on Flamsteed early in his career. See Willmoth, ‘Models for the practice of astronomy: Flamsteed, Horrocks and Tycho’, in Willmoth, op. cit. (2), pp. 49–75.

32 Dear, Peter, Discipline and Experience: The Mathematical Way in the Scientific Revolution, Chicago: The University of Chicago Press, 1995, pp. 9596CrossRefGoogle Scholar. On the importance of historical continuity in early modern astronomy also see Jardine, Nicholas, The Birth of History and Philosophy of Science: Kepler's A Defence of Tycho against Ursus with Essays on Its Provenance and Significance, Cambridge: Cambridge University Press, 1984Google Scholar, esp. Chapter 8.

33 Flamsteed to Collins, 23 July 1672, CJF, vol. 1.

34 Flamsteed to Oldenburg, 8 March 1671/2, CJF, vol. 1.

35 Flamsteed to Oldenburg, 2 December 1671, CJF, vol. 1.

36 Flamsteed to Oldenburg, 8 March 1671/2, CJF, vol. 1.

37 For an especially illustrative description of screw and nut production techniques from the time see Moxon, Joseph, Mechanick Exercises: or, The doctrine of handy-works, London, 1693–1694, pp. 2932Google Scholar; for secondary literarture on premodern screw production techniques see Brooks, Randall C., ‘Standard screw threads for scientific instruments: Part 1: Production techniques and the filière suisse’, History and Technology (1988) 5, pp. 5976, 61–62CrossRefGoogle Scholar; Brooks, ‘Origins, usage and production’, op. cit. (22), pp. 57, 60–65; Brooks, ‘The precision screw in scientific instruments of the 17th–19th centuries: with particular reference to astronomical, nautical and surveying instruments’, PhD dissertation, University of Leicester, 1989, OCLC 806501987, pp. 23–30, 56–75.

38 Flamsteed to Collins, 23 July 1672, CJF, vol. 1.

39 Brooks, ‘The development of micrometers’, op. cit. (22), pp. 130–134, offers an examination of the different thread pitches of different early filar micrometers.

40 In his Gresham lectures, Flamsteed told his listeners that ‘Mr Gascoigne … tooke his measures by the help of a Micrometer or payre of screws placed in ye inner focus of his telescope’. See Forbes, op. cit. (1), p. 197.

41 Flamsteed to Towneley, 11 December 1676, CJF, vol. 1. Flamsteed was in Greenwich – at the time a considerable distance from London.

42 Flamsteed to Towneley, 31 December 1676, CJF, vol. 1.

43 See, for example, Flamsteed to Moore, April 1674, CJF, vol. 1.

44 Flamsteed to Towneley, 15 February 1676/7, CJF, vol. 1.

45 This was not an uncommon form of assuming authorship for artisanal successes. In his Micrographia (1665), Hooke ascribed all of the failures in the engravings in his book to the engravers but maintained that in all other cases the engravers' work was merely that of copyists. See Dennis, Michael Aaron, ‘Graphic understanding: instruments and interpretation in Robert Hooke's Micrographia’, Science in Context (1989) 3, pp. 309364, 314Google Scholar.

46 A fine example of this tension in Flamsteed's career is that in the manuscript of his preface to the Historia Coelestis Britannica Flamsteed referred to his assistants as ‘Domestiks’. In preparing his manuscripts for publication after his death, Flamsteed's assitants, A. Sharpe, J. Hodgson and J. Crosthwaite, changed their titles to ‘Contubernalis’, ‘which translates as comrade, companion, associate or colleague’. See Chapman, The Preface, op. cit. (3), p. 206 n. 138. The fraught relationship between Descartes and Ferrier is a good example of this pattern outside Flamsteed's career. See Burnett, D. Graham, Descartes and the Hyperbolic Quest: Lens Making Machines and Their Significance in the Seventeenth Century, Philadelphia: American Philosophical Society, 2005, pp. 4169Google Scholar, esp. 52; Gauvin, Jean-François, ‘Artisans, machines, and Descartes's Organon’, History of Science (2006) 44, pp. 98201Google Scholar; Shea, William R., The Magic of Numbers and Motion: The Scientific Career of René Descartes, Canton: Science History Publications, 1991, pp. 191201Google Scholar.

47 Molyneux to Flamsteed, 3 December 1681, CJF, vol. 1.

48 Justel to Oldenburg, June 1667, CHO, vol. 3.

49 Justel to Oldenburg, June 1667, CHO, vol. 3.

50 Justel to Oldenburg, June 1667, CHO, vol. 3.

51 Flamsteed to Moore, April 1674, CJF, vol. 1.

52 Flamsteed to Moore, April 1674, CJF, vol. 1.

53 On the connection between patronage and scientific identity formation in the context of astronomy in the early modern period and as an interesting contrast to Flamsteed see Biagioli, Mario, ‘Galileo's system of patronage’, History of Science (1990) 28, pp. 162CrossRefGoogle Scholar; Biagioli, Galielo, Courtier: The Practice of Science in the Culture of Absolutism, Chicago: The University of Chicago Press, 1993Google Scholar, Chapter 1.

54 Flamsteed to Moore, April 1674, CJF, vol. 1.

55 There is an interesting contradiction to be pointed out here. When Towneley asked Flamsteed to construct a micrometer for Cassini, the Astronomer Royal declined at first, insisting that Humphrey Adamson did not construct the screws for his micrometer as well as those Adamson had produced for Towneley's micrometer (see above). If in his letter to Moore Flamsteed was referring to the same screws he acquired from Adamson that he later tells Towneley are not so well made, it may be the case that Flamsteed exaggerated to Moore the accuracy he could achieve with his micrometer, or Flamsteed was downplaying the quality of Adamson's work when he was asked to manufacture a micrometer for Cassini.

56 Probably, 908′ 7″ was the complete length of Flamsteed's surveyor's chain. This method was not of Flamsteed's invention; he learned it from Towneley. Flamsteed to Moore, April 1674, CJF, vol. 1.

57 Hevelius to Oldenburg, 19 November 1668, CHO, vol. 5. Hevelius struggled to get his hands on a micrometer. Three years after he first requested a micrometer from Oldenburg in the autumn of 1668, Hevelius reprimanded Oldenburg for persistently failing to send him the device. See, for example, Hevelius to Oldenburg, 27 September 1671, CHO, vol. 8.

58 Hevelius to Flamsteed, 9 January 1681/2, CJF, vol. 1. Hevelius also asked Dethlef Cluver in London for instructions on how to install his newly acquired micrometer in 1681. See Hevelius to Cluver, 1681, in Damian-Grint, Peter (ed.), Translations of Edmond Halley's Latin Correspondence (tr. Stainer, Alice), Oxford: Electronic Enlightenment Project, 2009Google Scholar, available at

59 Flamsteed to Hevelius, 28 March 1682, CJF, vol. 1.

60 Flamsteed to Hevelius, 28 March 1682, CJF, vol. 1.

61 Flamsteed to Hevelius, 28 March 1682, CJF, vol. 1.

62 Forbes, op. cit. (1), p. 149.

63 Forbes, op. cit. (1), p. 148.

64 Consider the following passage: ‘Especially a famous p[er]son [Hevelius] found himselfe p[ar]ticualrly touched by my recommendations of them [the micrometer and telescope] when I had published some new observations or measures taken with glasses & screws placed in their focus. Hee was pleased to urge me much against their use.’ Forbes, op. cit. (1), p. 149.

65 That Flamsteed considered Hevelius to be problematically entrenched in the ‘Tychonic tradition’ of astronomy is clearly articulated in several of Flamsteed's works. See, for example, Chapman, The Preface, op. cit. (3), pp. 105–109; Forbes, op. cit. (1), pp. 119, 132 n. 4.2, 149, 160 n. 7.7. All of the quotations refer to Dear, op. cit. (32), pp. 95–96.

66 Chapman, The Preface, op. cit. (3), p. 101.

67 Flamsteed to Wallis, 20 December 1698, CJF, vol. 2.

68 Wallis, John, Opera Mathematica, 3 vols., Oxford, 1699, vol. 3, pp. 701708Google Scholar.

69 His letter to Wren was, however, published posthumously in Wren, Stephen, Parentalia: or, memoirs of the family of the Wrens, London, 1750, pp. 248252Google Scholar; Williams, op. cit. (18), pp. 112–113.

70 Flamsteed to Wren, 19 November 1702, CJF, vol. 2.

71 Williams, op. cit. (18), pp. 113.

72 Vertesi, Janet, ‘Instrumental images: the visual rhetoric of self-presentation in Hevelius's Machina Coelestis’, BJHS (2010) 43, pp. 209243, 213, 228–229Google Scholar. Although Vertesi does not mention it, there is an important theoretical parallel to her work in Popplow's, MarcusWhy draw pictures of machines? The social contexts of early modern machine drawings’, in Lefèvre, Wolfgang (ed.), Picturing Machines, 1400–1700, Cambridge, MA: The MIT Press, 2004, pp. 1748Google Scholar.

73 Vertesi, op. cit. (72), p. 210; Van Helden, op. cit. (5), p. 10; Brahe, Tycho, Tychonis Brahe Astronomiae instauratae mechanica, Noribergae, 1602CrossRefGoogle Scholar.

74 For a detailed account of this episode see Shapin, Steven, A Social History of Truth: Civility and Science in Seventeenth-Century England, Chicago: The University of Chicago Press, 1995, pp. 266291Google Scholar.

75 Vertesi, op. cit. (72), pp. 212, 211.

76 Hevelius's Machina followed his Selenographia (1647), which, it has been argued, was the first early modern astronomical publication to develop a comprehensive and meticulous visual language for astronomical observation and instrumentation. See Winkler, Mary G. and van Helden, Albert, ‘Johannes Hevelius and the visual language of astronomy’, in Field, J.V. and James, Frank A.J.L. (eds.), Renaissance and Revolution: Humanists, Scholars, Craftsmen, and Natural Philosophy in Early Modern Europe, Cambridge: Cambridge University Press, 1993, pp. 97116Google Scholar.

77 Baily, op. cit. (8), p. 90.

78 On Flamsteed's history with and expulsion from the Royal Society see Mordechai Feingold, ‘Astronomy and strife: John Flamsteed and the Royal Society’, in Willmoth, op. cit. (2), pp. 31–48.

79 On the 1712 publication of the Historia Coelestis Libri Duo and Halley's pejorative preface see Johns, The Nature of the Book, op. cit. (2), pp. 598–611.

80 Chapman, The Preface, op. cit. (3), Appendix II, p. 192.

81 Chapman, The Preface, op. cit. (3), Appendix II, p. 192.

82 In the spring of 1716 Flamsteed collected all of the remaining copies of Halley's abridged version of his Historia, and on Greenwich Hill he burned all of the sheets he considered to be corrupted by Halley's intervention. This was, as he put it, a ‘sacrifice to TRUTH’. See Adrian Johns, The Nature of the Book, op. cit. (2), pp. 607–609; Flamsteed to Lowthorp, 3 February 1715/16, CJF, vol. 3; Baily, op. cit. (8), pp. xlii, 320–321.

83 Baily, op. cit. (8), p. xix.

84 Forbes, op. cit. (1), p. 147.

85 It is important to note that although this reading emphasizes the way in which the images in Flamsteed's preface and his rhetoric in the preface try to show how Flamsteed's work surpasses the Tychonic tradition, Flamsteed was still working within a general scheme of credit based on instrumentation that originated with Tycho. Another way to say this is that although Flamsteed was trying to base his credibility on the discontinuity between his astronomical praxis and that of the Tychonic tradition, his general rhetorical strategy was still operating within the Tychonic paradigm. I owe this point to an anonymous referee.

86 Vertesi, op. cit. (72), pp. 221, 227–230.

87 Hevelius was, of course, not the first to base the legitimacy of his observations on the quality of his eyes. Arguing about the true shape of Saturn, Galileo held that his observations were indeed correct because his eyesight and instruments were superior to those of his challengers. Drake, Stillman (ed.), Discoveries and Opinions of Galileo: Including The Starry Messenger (1610), Letter to the Grand Duchess Christina (1615), and Excerpts from Letters on Sunspots (1613), the Assayer (1623) (tr. Drake, Stillman), New York: Anchor Books, 1957, pp. 101102Google Scholar.

88 The typology of the early modern scientific observer as a sort of sage is borrowed from Daston, Lorraine and Galison, Peter, Objectivity, New York: Zone Books, 2007, pp. 55113Google Scholar.

89 Vertesi, op. cit. (72), p. 227; Winkler and Van Helden, op. cit. (76), p. 98.

90 Hooke, Robert, Animadversions, London, 1674, p. 8Google Scholar; Buchwald, op. cit. (7), pp. 613–622, offers an excellent analysis of Hooke's experiment.

91 Halley to Flamsteed, 7 June 1679, CJF, vol. 1 (emphasis added).

92 Halley to Flamsteed, 7 June 1679, CJF, vol. 1 (emphasis added); Derek Jensen points out that the major difference between the images in Hevelius's Selenographia and those in his Machina Coelestis Pars Prior is that the images in the latter feature Hevelius's assistants working with him in order to heighten the analogy between Hevelius and Tycho. To this we can add that the reason for the assistants in these images was also to show that the credibility of Hevelius's visual skills was supported by local witnesses. Derek Jensen, ‘The science of the stars in Danzig from Rheticus to Hevelius’, PhD dissertation, University of California, San Diego, 2006, UMI 3236816, p. 237; Vertesi, op. cit. (72), p. 216.

93 Saridakis argues that the controversy that arose between Hooke and Hevelius about the benefits of naked-eye sights versus telescopic sights forced the scientific community to take sides and thereby distinguish ‘the appropriate characteristics of astronomical practice and the appropriate activities of the astronomer’. See Saridakis, op. cit. (13), p. 10.

94 It is important to note that Flamsteed began drafting his preface as early as 1716, and he died at the end of 1719, making the second publication of his star catalogue posthumous. Although Flamsteed obviously did not have control over the publication of the 1725 Historia, its compilation and publication, which were organized by Flamsteed's wife, Margaret, and his two former assistants, Joseph Crosthwait and Abraham Sharp, who earned no recompense for their efforts, were very much devoted to the vindication of his reputation, and it was certainly published in the spirit of Flamsteed's research by the people who were the most intimately acquainted with it. In the spring of 1726, after the publication of the 1725 Historia, Margaret Flamsteed persisted in trying to vindicate her late husband. She wrote to Dr Mather, the vice chancellor at Oxford, asking for his copy of Halley's 1712 abridgement of Flamsteed's Historia, saying, ‘I am under an obligation not only to do justice to the memory of Mr. Flamsteed, but also to prevent the world's being imposed on by a false impression.’ See Baily, op. cit. (8), pp. 364 for the preceding quotation, 332–364 for relevant letters concerning the publication of Flamsteed's Historia following his death, 321 for Flamsteed beginning seriously to draft his preface in 1716. For a general account of the publication of the 1725 Historia see Johns, The Nature of the Book, op. cit. (2), pp. 611–617.

95 Forbes, op. cit. (1), p. 113.

96 The only real attention these etchings have received is by Derek Howse, in whose book there is a nearly complete reproduction of the whole series (only the original frontispiece is known to be missing). Howse, Derek, Francis Place and the Early History of the Greenwich Observatory, New York: Science History Publications, 1975Google Scholar.

97 We can be quite certain that at least some, if not all, of the other Place etchings were among Flamsteed's possessions when he passed away. Similarly, at the time Joseph Crosthwait was working on transcribing Flamsteed's preface and sending it off to be translated into Latin he was also certainly in possession of some of the Place etchings that were not included in the 1725 Historia. Howse, op. cit. (96), pp. 25–26; Baily, op. cit. (8), p. 343 for Crosthwait's possession of the place etchings, 333–338 for the letters concerning the transcription and translation of Flamsteed's preface.

98 In spite of this, the general point I am about to make also holds for others of the Place etchings when compared with the images in Hevelius's Machina. For Flamsteed's descriptions of the Place etchings that were included in the 1725 Historia see Chapman, The Preface, op. cit. (3), pp. 113, 116, 118.

99 Chapman, The Preface, op. cit. (3), p. 124.

100 Flamsteed to Wallis, 20 December 1698, CJF, vol. 2; Wallis, op. cit. (68), vol. 3, pp. 701–708.

101 Chapman, The Preface, op. cit. (3), p. 111.

102 For some of the problems associated with making astronomical observations publicly accessible in the seventeenth century see Winkler, Mary G. and van Helden, Albert, ‘Representing the heavens: Galileo and visual astronomy’, Isis (1992) 83, pp. 195217Google Scholar; Van Helden, op. cit. (5); on the importance of the activities of natural philosophers being considered publicly accessible in general in the seventeenth century see Shapin, Steven and Schaffer, Simon, Leviathan and the Air-Pump: Hobbes, Boyle, and the Experimental Life, Princeton: Princeton University Press, 1985, pp. 5560Google Scholar.

103 Chapman, The Preface, op. cit. (3), p. 116.

104 Chapman, The Preface, op. cit. (3), p. 116.

105 Flamsteed's scepticism about whether or not artisans could actually contrive a device that was not inherently flawed can be compared to Descartes's reluctance to trust lens makers to craft lenses that would not create optical distortions. According to Burnett, ‘Descartes made the artisan responsible for the gap between theory and praxis, and then tried to close the gap by a mechanical device’ – i.e. lens-grinding machines. See Burnett, op. cit. (46), p. 125. It is, however, interesting to point out that Flamsteed doubted the ability of artisans to manufacture mechanical devices in general (and graduated arcs in particular) of sufficient quality to eliminate instrumental errors in observation. That Flamsteed refers to telescopes as the means of achieving ‘ultimate perfection’ seems to ignore the fact that lenses too were contrived by human artifice. Flamsteed does acknowledge that the work of lens grinders is too imperfect, but this does not seem to inhibit his convictions about the perfection of telescopic sights. See Forbes, op. cit. (1), pp. 151–152; Chapman, The Preface, op. cit. (3), p. 116.

106 Burnett, op. cit. (46), p. 52.

107 Buchwald makes a similar observation: Flamsteed ‘was from the outset deeply concerned with locating and minimizing the “errors” in his instruments … In fact, Flamsteed seems to have attributed most differences between observational values taken at different times with the same device to errors of this sort’. See Buchwald, op. cit. (7), p. 578.

108 Flamsteed to Molyneux, 2 September 1681, CJF, vol. 1. On Flamsteed and Molyneaux's relationship see Johns, ‘Flamsteed's optics’, op. cit. (2), pp. 87–93.

109 Flamsteed to Molyneux, 2 September 1681, CJF, vol. 1.

110 Buchwald, op. cit. (7), p. 580, has also noted that Flamsteed took averages of his observations.

111 Buchwald, op. cit. (7), p. 585.

112 Buchwald, op. cit. (7), pp. 589–590 (emphasis in original).

113 The wording for this sentence is anachronistically borrowed from Bernard, Claude, the nineteenth-century physiologist, who is quoted saying, ‘the observer no longer reasons; he registers’, in Daston, Lorraine and Lunbeck, Elizabeth, Introduction to Daston and Lunbeck (eds.), Histories of Scientific Observation, Chicago: The University of Chicago Press, 2011, pp. 1–9, 4Google Scholar.

114 Chapman, The Preface, op. cit. (3), p. 106.

115 Chapman, The Preface, op. cit. (3), p. 118.

116 Chapman, The Preface, op. cit. (3), p. 118.

117 Chapman, The Preface, op. cit. (3), p. 119.

118 Flamsteed also used a similar strategy with his micrometer. See, for example, Flamsteed to Hevelius, 28 March 1682, CJF, vol. 1.

119 Chapman, The Preface, op. cit. (3), p. 119.

120 Chapman, The Preface, op. cit. (3), p. 124.

121 Chapman, The Preface, op. cit. (3), p. 125.

122 Chapman, The Preface, op. cit. (3), p. 141.

123 Chapman, The Preface, op. cit. (3), p. 141.

124 Saridakis, op. cit. (13), p. 10.

125 Reeves, Nicky, ‘“To demonstrate the exactness of the instrument”: mountainside trials in Scotland, 1774’, Science in Context (2009) 22, pp. 323340Google Scholar.

126 Quoted in Reeves, op. cit. (125), p. 332.

127 Schaffer, Simon, ‘Astronomers mark time: discipline and the personal equation’, Science in Context (1988) 2, pp. 115145Google Scholar; Canales, Jimena, A Tenth of a Second, Chicago: The University of Chicago Press, 2009Google Scholar, Chapter 2.

128 Although not using the terminology of the ‘mechanization of observation’, Ofer Gal and Raz Chen-Morris have argued that a similar process was taking place in the early seventeenth century. See ‘Empiricism without the senses: how the instrument replaced the eye’, in Charles Wolfe, T. and Gal, Ofer (eds.), The Body as Object and Instrument of Knowledge: Embodied Empiricism in Early Modern Science, Dordrecht: Springer, 2010, pp. 121148Google Scholar.

129 Daston and Galison, op. cit. (88), pp. 115–190. Although Daston and Galison limit their discussion of objectivity to the images produced in scientific atlases, there is no reason to think that the concept of objectivity that they idenitfy as well as the concept's historical precursors should be limited to strictly visual representations in science: ‘In this book, we trace the emergence of epistemic virtues through atlas images – by no means the only expression of truth-to-nature or objectivity or trained judgement’. Daston and Galison, op. cit. (88), p. 27.

130 Schaffer, op. cit. (127), pp. 115, 119, is responsible for the expression ‘mechanization of observation’ in relation to the events following the discovery of the personal equation. See also Canales, op. cit. (127), Chapter 2.

131 Compare the foregoing analysis of Flamsteed's attitude toward the appropriate behaviour of the positional astronomer with Daston and Galison's characterization of mechanical objectivity: ‘By mechanical objectivity we mean the insistent drive to repress the willful intervention of the artist–author, and to put in its stead a set of procedures that would, as it were, move nature to the page through a strict protocol, if not automatically.’ Daston and Galison, op. cit. (88), p. 121 (emphasis in original).