Catadioptrics and Commerce in Eighteenth-Century London

For information on the more obscure makers of London, see Clifton Gloria , Directory of British scientific instrument makers 1550–1851 (London, 1995); see also Taylor E. G. R. , The mathematical practitioners of Hanoverian England (Cambridge, 1966).

Hooke Robert , The posthumous works, ed. by Waller R. (London, 1705), 557; Sprat Thomas , The history of the Royal Society (London, 1667), 246. It has also been attributed to Halley, see Ronan Colin A. , Edmond Halley, genius in eclipse (London, 1970), 35–36.

Confusingly both terms, ‘octant’ and ‘quadrant’, are used for this instrument. The length of the arc scale on the instrument covers 45 degrees (so it is an ‘octant’), but as we shall see, the scale is divided and numbered at twice the rate of the physical angle, thus reaching 90 degrees in all (so it is also a ‘quadrant’).

Birch Thomas (ed.), The history of the Royal Society (London, 1756–57), ii, 113; Hooke , op. cit. (ref. 2), 503.

Birch , op. cit. (ref. 4), ii, 447.

Reliable accounts of the various early configurations of reflecting instruments can be found in Cotter Charles H. , A history of the navigator's sextant (Glasgow, 1983), 104–31, and in Ifland Peter , Taking the stars (Newport News, 1998), 12–18.

Royal Society ms, JBC, viii, 103; Sprat , op. cit (ref. 2), 246; MacPike Eugene F. (ed.), Correspondence and papers of Edmond Halley (Oxford, 1932), 161–2; Ronan , op. cit. (ref. 2), 129–30; Cook Alan , Edmond Halley: Charting the heavens and the seas (Oxford, 1998), 219. Cook seems to be wrong in saying that Hooke “had done nothing about” his design, as it seems that an instrument, or at least a model, was being examined in 1670, Birch , History (ref. 4), ii, 447.

Royal Society ms, JBC, ix, 171.

Cook , op. cit. (ref. 7), 267.

Royal Society ms, JBC, ix, 171. See also Waters D. W. , “Captain Edmond Halley, F.R.S, Royal Navy, and the practice of navigation”, in Thrower N. J. W. (ed.), Standing of the shoulders of giants: A longer view of Newton and Halley (Berkeley, 1990), 171–202.

Royal Society ms, JBC, ix, 171.

Simpson A. D. C. , “Robert Hooke and practical optics: Technical support at a scientific frontier”, in Hunter Michael Schaffer Simon (eds), Robert Hooke: New studies (Woodbridge, 1989), 33–61. On Newton's telescope, see Hall A. R. Simpson A. D. C. , “An account of the Royal Society's Newton telescope”, Notes and records of the Royal Society of London, 1 (1996), 1–11.

Bennett J. A. , “Hooke's instruments for astronomy and navigation”, in Hunter Schaffer (eds), op. cit. (ref. 12), 21–32.

Bennett J. A. , “The instrument trade in Britain”, Annals of science, liv (1997), 197–206.

Smith Robert , Compleat system of opticks in four books (Cambridge, 1738), 301–12.

Hadley John , “An account of a catadioptrick telescope”, Philosophical transactions, xxxii (1722), 303–12.

Royal Society ms, Cl.P/2/16.

Westfall Richard S. , Never at rest: A biography of Isaac Newton (Cambridge, 1980), 832.

Pound James , “A letter … concerning observations made with Mr. Hadley's reflecting telescope”, Philosophical transactions, xxxii (1722), 382–4.

Hadley John , “Observations on the satellites of Jupiter and Saturn, made with the same telescope”, Philosophical transactions, xxxii (1722), 385–6.

Desaguliers John Theophilus , “Appendix” to David Gregory, Elements of catoptrics and dioptrics (London, 1735), 211–88.

It is worth noting that Desaguliers adds the annotation: “The Reason why Mr. Hadley uses a double Eye-Glass instead of a single one proposed by Dr. Gregory, is, to prevent the object being coloured at the Edges of the Aperture”, supporting the claims from opticians that correction for chromatic aberration was practised in the trade before Dollond took out his patent in 1758, Desaguliers , op. cit. (ref. 21), 252.

Smith , op. cit. (ref. 15), 302–3.

Smith , op. cit. (ref. 15), “The author's remarks upon the whole work”, 80.

von Uffenbach Zacharias Conrad , London in 1710 from the travels of Zacharias Conrad von Uffenbach, ed. by Quarrell W. H. Gore M. (London, 1934), 168.

Smith Caleb , “A new method of improving and perfecting catadioptrical telescopes”, Philosophical transactions, xli (1740), 326–40, pp. 339–40.

For Short, see Turner G. L'E. , “James Short, FRS, and his contribution to the construction of reflecting telescopes”, Notes and records of the Royal Society of London, xxiv (1969), 91–108; Bryden D. J. , “James Short, MA, FRS, optician solely for reflecting telescopes”, University of Edinburgh journal, xxiv (1969–70), 251–61.

Mudge John , “Directions for making the best composition for the metals of reflecting telescopes; together with a description of the process for grinding, polishing, and giving the great speculum the true parabolic curve”, Philosophical transactions, lxvii (1777), 296–349; King Henry C. , The history of the telescope (New York, 1979), 89–91.

Hadley John , “The description of a new instrument for taking angles”, Philosophical transactions, xxxvii (1731), 147–57.

Cook , op. cit. (ref. 7), 401–2. A valuable account of Royal Society activity in this field is Cotter Charles H. , “The mariner's sextant and the Royal Society”, Notes and records of the Royal Society of London, xxxiii (1978), 23–36.

Royal Society ms, JBC, xiii, 602. George Hadley had last been introduced in this way on 29 January 1729/30, ibid., 398; he became a Fellow in 1735.

Royal Society ms, RBO, xvii, 443; JBC, xiii, 602.

Streete Thomas , Astronomia Carolina: A new theory of the cælestial motions (London, 1710), “Appendix”, 67–69; Royal Society ms, RBO, xvii, 443–52; Halley Edmond , “A proposal of a method for finding the longitude at sea within a degree, or twenty leagues”, Philosophical transactions, xxxvii (1731), 185–95.

Royal Society ms, RBO, xvii, 452.

Royal Society ms, JBC, xiii, 606; Cl.P/2/21.

Royal Society ms, Cl.P/2/21.

Royal Society ms, JBC, xiii, 609.

Royal Society ms, JBC, xiii, 616–17.

Hadley , op. cit. (ref. 29).

Royal Society ms, EL/H4/24.

Royal Society ms, JBC, viii, 37.

Halley , op. cit. (ref. 33), 185–95.

Royal Society ms, JBC, viii, 37; see also pp. 61–63.

Royal Society ms, JBC, viii, 197–9; Hadley John , “An account of observations made on board the Chatham-Yacht”, Philosophical transactions, xxxvii (1731), 341–56.

Ibid., 351.

Smith , op. cit. (ref. 15), 368–77.

Desaguliers , op. cit. (ref. 21), 256.

Ludlam William , Directions for the use of Hadley's quadrant (London, 1790), preface.

Ibid., 2. For a recent study of the acceptance of the octant, see Clifton Gloria , “The adoption of the octant in the British Isles”, in Daalder Remmelt (eds), Koersvast: Vift eeuwen navigatie op zee (Zaltbommel, 2005), 85–94.

Ludlam , op. cit. (ref. 48), 3.

The Whipple Museum of the History of Science has an early octant, with a diagonal scale on box wood, signed by John Goater of Wapping, Wh: 355; a similar instrument by Edward Nairne is in the Museum of the History of Science, Oxford, inv. 40933; see also Clifton , op. cit. (ref. 49); Ifland , Taking the stars (ref. 6), 46; National Maritime Museum, An inventory of the navigation and astronomy collections (Greenwich, 1970), section 22.

Elton John , “The description of a new quadrant for taking altitudes without an horizon, either at sea or land”, Philosophical transactions, xxxvii (1731), 273–9; Leigh Charles , “A description of a water-level to be fix'd to a Davis's quadrant”, Philosophical transactions, xl (1738), 413–17; “The description and use of an apparatus added as an improvement to the Davis's quadrant”, ibid., 417–24; see also Royal Society ms, CP, viii (2), 59, 73. For the neo-backstaff, see Godfrey's modification of the mariner's bow below.

Royal Society ms, JBC, viii, 38–44. Elton's paper was read over two meetings, it was endorsed by Hodgson James , and a revised version submitted for publication in July 1732, Royal Society ms, EL/E/11; RBO, xvi, 235–47.

Bryden David J. , “Patents for scientific instruments in Georgian England”, in preparation.

Adams George , Description and use of a new sea quadrant (London, 1748); Cole Benjamin , The description and use of a new quadrant, for finding the latitude at sea (London, 1749).

In c. 1757 Adams noted that diagonal division was “so well understood, as to require no explanation”, but he did explain the vernier, “as many of them [Hadley quadrants] are subdivided by means of a Nonius Division to every single Minute”, Adams George , Instructions for the use of Hadley's quadrant (London, c. 1757).

Royal Society ms, JBC, viii, 76, 83–87; RBO, xvi, 357–62.

Royal Society ms, JBC, viii, 89, 285–6. For Plank, see also Taylor , op. cit. (ref. 1), 139; Stewart Larry , The rise of public science: Rhetoric, technology, and natural philosophy in Newtonian Britain, 1660–1750 (Cambridge, 1992), 140, 201.

Royal Society ms, EL/L6/59.

Ibid. On Godfrey's invention, see Bedini Silvio A. , At the Sign of the Compass and Quadrant: The life and times of Anthony Lamb (Transactions of the American Philosophical Society, lxxiv/1 (1984)), 37–44.

Elton , op. cit. (ref. 52), 277–9.

Royal Society ms, JBC, viii, 362–4 (10 January 1733/4); Hadley John , “A spirit level to be fixed to a quadrant for taking a meridional altitude at sea, when the horizon is not visible”, Philosophical transactions, xxxviii (1733), 167–72.

Royal Society ms, JBC, viii, 374–8.

Royal Society ms, JBC, viii, 378–80.

Godfrey Thomas Logan James , “An account of Mr. Thomas Godfrey's improvement of Davis's quadrant, transferred to the mariner's-bow”, Philosophical transactions, xxxviii (1738), 441–50; note also Royal Society ms, CP, viii (2), 48.

Bryden , op. cit. (ref. 54). See also Clifton , op. cit. (ref. 49), 89.

Cotter , op. cit. (ref. 6), 127–9; Ifland , op. cit. (ref. 51), 13–15; Talbot Stuart , “Caleb Smith's sea quadrants of c. 1735 as constructed by Thomas Heath and George Adams Snr of London”, Bulletin of the Scientific Instrument Society, no. Ixxiii (June 2002), 2–7.

Smith Caleb , The description, use, and excellency of a new instrument, or sea quadrant (London, 1735).

Smith Caleb Ward William , The description and use of a new astronomical instrument, for taking altitudes of the sun and stars at sea, without an horizon (London, 1735).

Smith , op. cit. (ref. 68), 3.

Ibid., 3–4.

Ibid., 3–4.

Millburn John R. , Adams of Fleet Street, Instrument Makers to King George III (Aldershot, 2000), 18–19.

Middleton Christopher , “Observations made of the latitude, variation of the magnetic needle, and weather”, Philosophical transactions, xxxix (1735), 270–80. In September 1736, Middleton was using the Hadley quadrant and Smith's prismatic quadrant at Bay Hudson's Graham George , “A collection of the observations of the lunar eclipse, Sept. 8, 1736”, Philosophical transactions, xl (1737), 96.

Halley , op. cit. (ref. 33), 189.

Desaguliers , op. cit. (ref. 21), 256; the Collection of Historical Scientific Instruments at Harvard University has an octant by Sisson with an ink note on paper pasted on to the frame stating that it was tried at sea by Hadley George in 1735, information from Dr Sara Schechner.

Hadley George , A description of a new instrument for taking the latitude or other altitudes at sea. With directions for its use (London, 1734); Hadley George , Descriptio astrolabii nautici novi a Johanne Hadley … inventi (London, 1734).

Hadley George , A description of a new instrument, invented by John Hadley, Esq; for taking the latitude or other altitudes at sea. With directions for its use (London, 1738). For octants by Gilbert John of Tower Hill, see Holbrook Mary , Science preserved (London, 1993), 128, 195, 211, 217, 233; Brewington M. V. , The Peabody Museum collection of navigating instruments (Salem, 1963), 10, 12, 13.

Royal Society ms, MM. 16.110; Newton Isaac , “A true copy of a paper found, in the hand writing of Sir Isaac Newton …”, Philosophical transactions, xlii (1742), 155–6. One difference between Newton's scheme and both of the others is that Newton has the mirrors parallel when the index arm is closest to the telescope, so the reading moves to 90 as the arm is drawn away from the telescope.

The correspondence of Isaac Newton, vi, ed. by Hall A. R. Tilling L. (Cambridge, 1976), 161–3.

Royal Society ms, JBO, xviii, 444–5.

Royal Society ms, JBO, 445; MM.16.110; for a recent example, see Clifton , op. cit. (ref. 49), 88.

Newton , op. cit. (ref. 79). The copy of the paper made for the Philosophical transactions is at Royal Society ms, L&P, i, 120; it is accompanied by a wash drawing of the instrument as it was printed, except that the scale on the limb is numbered to 45, not to 90 degrees.

Adams , Instructions (ref. 56); John Dollond & Son, The construction and use of the sea quadrant, commonly called Hadley's quadrant (London, 1760); Martin Benjamin , The theory of Hadley's quadrant demonstrated (London, c. 1761).

Clifton , op. cit. (ref. 1), 196.

Martin Benjamin , A catalogue of philosophical, optical, and mathematical instruments (London, no date); Millburn John , Benjamin Martin: Author, instrument-maker, and ‘country showman’ (Leiden, 1976), 117; Clifton , op. cit. (ref. 1), 181. Martin's ‘visual glasses’ were his design of spectacles.

Millburn , op. cit. (ref. 73), 44–45.

Clifton , op. cit. (ref. 1), 87.

Millburn , op. cit. (ref. 73), 79.