Simon Newcomb,William Harkness and the Nineteenth-Century American Transit of Venus Expeditions

For a history of cosmic dimensions from Antiquity to the seventeenth century, see Van Helden Albert , Measuring the universe: Cosmic dimensions from Aristarchus to Halley (Chicago and London, 1985). On modern determinations, which are made by radar with independent confirmation from spectroscopy, see Knowles Stephen H. , “Determination of the astronomical unit from hydrogen-line radial velocity measurements”, Ph.D. dissertation, Yale University, 1968. Chapter 2 gives a history of astronomical unit determinations.

Van Helden , op. cit . (ref. 1), 161. On the parallax determinations of 1672 see Van Helden's Chapter 12, and the conclusion in Chapter 14.

Newcomb Simon , Popular astronomy (New York, 1884), 171–2. The Naval Observatory and others nevertheless sponsored many transit of Mercury observations, not for the determination of the astronomical unit, but for comparing the theory of Mercury's orbit with observation. See Washington observations for 1876 (Washington, 1879), Publications of the U.S. Naval Observatory , vi (Washington, 1911), App. 2, and idem , xv/2 (Washington,1942).

On the history of determinations of the Sun's distance in the nineteenth century see Clerke Agnes , History of astronomy during the nineteenth century 4th edn (London, 1902), Chapter 6, from which this quote is taken. For general aspects of the transits of Venus see Proctor R. A. Transits of Venus: A popular account of past and coming transits 4th edn (London, 1882). For the eighteenth-century expeditions see Woolf Harry , The transits of Venus: A study of eighteenth-century science (Princeton, 1959); on the observation of the 1769 transit of Venus in America, see Hindle Brooke , The pursuit of science in revolutionary America (New York, 1974), 146–65. Van Helden , op. cit . (ref. 1), 161, concludes that the eighteenth-century transit of Venus expeditions gave “the very first positive determination a parallax other than the Moon's Newcomb reviewed the eighteenth-century transit of Venus results in his “Discussion of observations of the transit of Venus in 1761 and 1769”, Astronomical papers prepared for the use of the American Ephemeris and Nautical Almanac , ii (Washington, 1890), 259–405. Newcomb further discusses the subject in his Popular astronomy (ref. 3), 178–84. See, also, Van Helden A. , “Measuring solar parallax: The Venus transits of 1761 and 1769 and their nineteenth-century sequels” in René Taton Wilson Curtis (eds), The general history of astronomy , ii: Planetary astronomy from the Renaissance to the rise of astrophysics. Part B: The eighteenth and nineteenth centuries (Cambridge, 1995), 153–68.

Airy G. B. , “On the means which will be available for correcting the measure of the Sun's distance, in the next twenty-five years”, Monthly notices of the Royal Astronomical Society , xvii (1857), 208–21; Clerke , op. cit . (ref. 4), 234. For details of the Russian method and instruments see Struve to Newcomb, 16 March 1872, U.S. National Archives, Records of the U.S. Naval Observatory, Record Group (RG) 78, E-18, Box 40, item 24. Struve notes that he had sent copies of the Russian observing protocols to USNO the previous summer. As of March, Struve wrote that the principal instruments were already ordered, and expected within a year. Archives related to the preparations, observations and analysis of American Transit of Venus parties for 1874 and 1882 are found in 21 boxes, labelled Box 27-Box 47, in the Naval Observatory Records, U.S. National Archives, Record Group 78, E-18, “Records of astronomical observations made chiefly in and near Washington, with subsequent computations and compilations, January 1845–June 1907”. Not all of the transit of Venus observations, of course, were made “in and near Washington”.

Gilliss's measurements, reduced by Gould, are found in “The solar parallax, deduced from observations of the U.S. Naval Astronomical Expedition, under Lt. J. M. Gilliss”, in The U.S. naval astronomical expedition to the southern hemisphere , iii (Washington, 1856), pp. lix–cclxxxviii. Hall's are in his “Solar parallax, deduced from observations of Mars with equatorial instruments”, Washington observations for 1863 (Washington, 1865), App. A. Newcomb's are in “Investigation of the distance of the Sun and of the elements which depend upon it”, Washington observations for 1865 (Washington, 1867), App. II.

Newcomb Simon , “On the mode of observing the coming transits of Venus”, American journal of science , 2nd ser., 1 (July-Nov. 1870), 74–83; idem, The reminiscences of an astronomer (London, 1903), 160–1. See also Janiczek P. M. Houchins L. , “Transits of Venus and the American expedition of 1874”, Sky & telescope , xlviii (1974), 366–71, and Janiczek , “Remarks on the Transit of Venus Expedition of 1874”, in Dick S. Doggett L. (eds), Sky with ocean joined (Washington, 1983), 53–73.

Naval Act dated 3 March 1871, Statutes at large , xvi, 520.

Harkness records that he was appointed to the Commission on 13 November 1871; see his “Biographical memorandum”, reprinted in the obituary by Skinner A. N. , Science , xvii (1903), 601–4.

Lankford John , “Photography and the 19th-century transits of Venus”, Technology and culture , xx (1987), 648–57. On the rise of photography in astronomy, see Norman D. , “The development of astronomical photography”, Osiris , v (1938), 560–94, and Lankford John , “The impact of photography on astronomy”, in Gingerich O. (ed.), The general history of astronomy , iv: Astrophysics and twentieth-century astronomy to 1950 , Part A (Cambridge, 1984), 16–39.

Sands Rutherfurd , 19 January 1872; Rutherfurd to Sands, 23 January 1872; Rutherfurd to Sands, 11 February 1872, in U.S. Commission on the Transit of Venus, Papers relating to the transit of Venus in 1874 , Part I (Washington, 1872), 8–13. The original Rutherford correspondence is found in the U.S. National Archives, Record Group 78, E-18, Box 40 (ref. 5), items 2, 11, 15, 19 and 31. On Rutherfurd see Warner Jean Deborah , “Lewis M. Rutherfurd: Pioneer astronomical photographer and spectroscopist”, Technology and culture , xii (1971), 190–216. Part II (Washington, 1872) of the Transit of Venus papers consists of charts and tables predicting details of the transits of Venus, by Hill G. W. of the Nautical Almanac Office. Part III, by Newcomb, was his “Investigation of corrections to Hansen's tables of the Moon, with tables for their application” (Washington, 1876), to be used in analysing the occultation observations for determining the longitude of the various stations.

Newcomb , Popular astronomy (ref. 3), 185–90; Newcomb , “On the application of photography to the observation of the transits of Venus”, in Papers (ref. 11), Part I, 14–25. The pipes were screwed together and one end came within 6 inches of the photographic plate and the other end to within 6 inches of the lens, with the intervening distances measures by a micrometer designed by Harkness.

Sands Robeson SecNav George M. , 5 March 1872, in Papers (ref. 11), Part I, 7–8. For correspondence relating to drafting the “Memorial to Congress” and other issues, see RG 78, E-18, Box 40 (ref. 5).

“History of the operations” in Newcomb Simon (ed.), Observations of the transit of Venus, December 8–9, 1874 made and reduced under the direction of the commission created by Congress (Washington, 1880), 9–10. In February 1874 Admiral Davis replaced Admiral Sands on the Transit of Venus Commission, and in May 1877 Admiral Rodgers replaced Admiral Davis. In 1874 Patterson C. P. replaced Peirce, and in 1879 William Rogers B. replaced Henry, who died in May 1878. See also Sundry Civil Act, June 10, 1872, Statutes at large , xvii, 367, under Transit of Venus Commission; Legislative Act dated March 3, 1873, Statutes at large , xvii, 514, under Transit of Venus Commission; and Sundry Civil Act, June 23, 1874, Statutes at large , xviii, Part 3, p. 210, under Miscellaneous.

The U.S. National Archives holds 152 items of “Letters received” related to preparations for the 1874 Transit of Venus expeditions, many addressed to Newcomb or Sands. RG 78, E-18, Box 40 (ref. 5) covers the period 23 January 1872 – 28 June 1873. Box 41 holds correspondence dated May 1875 — Feb. 1878, as well as letters turned over to the U.S. Naval Observatory by Newcomb.

As early as February 1872, Clark gave Sands a rough estimate of $1000 for each 5-inch refractor, and $350 for each photoheliograph. Clark to Sands, 14 February 1872, RG 78, E-18, Box 40, item 12 (ref. 5). The actual contract was executed on 9 May 1873 for instruments to be delivered by 1 March 1874. The eight 5-inch achromatic telescopes were to be 70 inches in focal length, “mounted on portable universal equatorial stands, furnished with driving clocks, divided circles, finders, eye-pieces, and micrometers. The declination circles to read to single minutes of arc, the R.A. circles, to 5 seconds of time.” The cost was $1200 each. The chronographs, made from the design of Harkness, cost $500 each. For another $80, Clark also supplied eight 2.5-inch lenses with 30-inch focal length and eight rectangular prisms for the portable transit, without mounting. The same contract specified eight 40-ft photoheliographs, but because the Clarks had never before constructed this instrument, a price was to be agreed upon only after the first instrument was constructed. RG 78, E-18, Box 40, item 134. Item 138 (dated 24 May 1873) is a contract with Edward Kahler for 8 dip circles and 8 observing keys for making or breaking a circuit. He also provided the eyepieces for the portable transits at $30 each, and the portable declinometers. The contract with Stackpole Bros, of New York, dated 18 June 1873 (item 145), provided for eight small theodolites at $200 each; eight portable transit instruments, with optics furnished by Clark, price to be determined after the first is made; and eight engineers levels at $175 each.

Lankford , op. cit. (ref. 10); Annual report of the Secretary of the Navy [hereafter AR; all published in Washington] (1872), 94; AR (1873), 94; AR (1874), 68–69. Newcomb, Popular astronomy (ref. 3), 188; Newcomb , Reminiscences (ref. 7), 167. Faye had independently invented the horizontal telescope in France. The American photographic instrument is described in more detail, with figures, in Newcomb, Observations (ref. 14), Chapter 3, 25ff.

Newcomb , “History”, in Observations (ref. 14), 14–15. The contract for the Howard clocks, at $275 each, is dated 1 May 1873, in RG 78, E-18, item 115. They were to be “provided with gravity escapements” made in accordance with drawings furnished by the Commission, with “Mercurial compensation pendulum each weighing not less than forty pounds”. All instruments were contracted for May and June 1873.

Regarding the Vladivostok site, Struve wrote [probably to Newcomb] on 4 Feb. 1873 that “we astronomers would be very glad if the American commission would occupy a station in the neighbourhood of ours on the Russian Coast of the Pacific Ocean. A very valuable control on the difficult methods of obtaining heliographic determinations would thus be gained. Our government is also well disposed in this regard, and the Grand Duke Constantine, with whom I spoke on the subject, has authorised me to propose that the coast region Wladivostok should be chosen as principal station on the part of the Americans.” Vladivostok was recommended for its favourable weather, the shortness of the period during which the harbour was closed in winter, and its accurate geographic determination. Struve also wrote, “I am rejoiced to learn from your letter that you have obtained so satisfactory results from the application of the long telescope. This method is also recommended by the comparative cheapness of the necessary apparatus. Nevertheless I do not think I have sufficient reason to give up the English method (De la Rue's).” Translated excerpt from Struve's letter, RG 78, E-18, Box 40. Other items related to the choice of stations are also filed in Box 40.

Newcomb , “History”, in Observations (ref 14), 16. Much correspondence in E-18, Box 40 relates to choice of personnel.

Newcomb , Reminiscences (ref. 7), 170–1; AR (1874), 69. The artificial apparatus is described in more detail in Newcomb, “History”, in Observations (ref. 14), 120–34; see also pp. 16–17. Records of contact observations are given in Observations , 145–57.

For the details of the Campbell Town expedition see Orchiston Wayne Buchanan Alex , “Illuminating incidents in antipodean astronomy: Campbell Town, and the 1874 transit of Venus”, Australian journal of astronomy , v (1993), 11–31.

For the chronology of the Swatara, see Newcomb , “History”, in Observations (ref. 14), 17–20.

Commission on the Transit of Venus, Instructions for observing the transit of Venus, December 8–9, 1874 (Washington, 1874).

For a detailed account of this transit station see Orchiston Wayne Love Tom Steven Dick J. , “Refining the astronomical unit: Queenstown and the 1874 transit of Venus”, in press.

On Peters see Warner Deborah J. , “Christian Heinrich Friedrich Peters”, in Dictionary of scientific biography , x (New York, 1974), 543, and Ashbrook Joseph , The astronomical scrapbook (Cambridge, Mass., 1984), 56–66.

Peters C. H. F. , “Section VII: Observations made at Queenstown”, in Newcomb Simon (ed.), Observations of the transit of Venus, December 8–9, 1874, made and reduced under the direction of the commission created by Congress. Part II. Sections 5–7 (unpublished typescript, Washington, 1881), 530, 548.

Peters C. H. F. , “General journal of the operations of the New Zealand party from their arrival at Bluff Harbour until Dec. 31, 1874” (manuscript in U.S. Naval Observatory Library, in Queenstown Transit of Venus Box).

See the map in Peters , op. cit. (ref. 27), 519.

See the site plan in Peters , op. cit. (ref. 27), 517.

The foregoing summary is based on entries in Peters , op. cit. (ref. 27), the “Daily journal” (1874) in Bass E. W. , “Photographic record and journal New Zealand party” (manuscript in U.S. Naval Observatory Library, in Queenstown Transit of Venus Box), and data in Newcomb, op. cit. (ref. 14), Chapter 1.

Twenty selected pairs of stars were observed between 12 and 30 November in order to determine the station's latitude. See Peters , op. cit. (ref. 27), 500–9.

Details of the telegraphic exchanges are provided in Peters, op. cit. (ref. 27), 479–99.

Peters , op. cit. (ref. 27), 530.

Peters C. H. F. Davis Rear-Admiral C. H. , 11 December 1874, in Peters, op. cit. (ref. 27), 439–40.

AR (1875), 80. For the details of the photographs from the various stations see Newcomb, “Discussion of the photographic observations”, in Observations (ref. 14), 77–84. Note that Todd used only 45 of the Queenstown photographic plates for his analysis. See Todd D. P. , “The solar parallax as determined from the American photographs of the transit of Venus, 1874, December 8–9”, American journal of science , xxi (1881), 491–3.

These are listed in Newcomb, op. cit. (ref. 14), 135.

Newcomb , op. cit. (ref. 14), 19.

AR (1875), 80–81. On Lindsay see Lindsay Lord Gill David , “On Lord Lindsay's preparations for observations of the transit of Venus, 1874”, Monthly notices of the Royal Astronomical Society , xxxiii (1872), 34–45.

Harkness W. , “Address by William Harkness”, Proceedings of the AAAS 31st Meeting … August 1882 (Salem, 1883), 77; Newcomb , quoted in AR (1875), 80–81.

Harkness , op. cit. (ref. 40), 86.

Harkness , op. cit. (ref. 40), 86–87; AR (1876), 97; AR (1877), 114. The French also reported their photographic results in 1885, publishing a value of 8.81 ± 0.06”. See Obrecht A. , “Discussion des resultats obtenus avec les épreuves daguerriennes de la Commission française du passage de Venus de 1874”, Comptes rendus , c (1885), 227–30; see also ibid., 341–3 and (for the final result) 1121.

Todd , op. cit. (ref. 36) pointed out that in order to reach his value provisional values had been adopted for longitudes of the stations, as well as other small corrections.

Newcomb , Reminiscences (ref. 7), 177–80. The Statutes at large show that $3000 had been appropriated for reducing observations in January 1875; $5000 in March 1877; $1000 for illustrations in 1878; and $950 in February 1881 “to finish the computations of the second part of the transit of Venus observations, and to complete them for publication”.

The results were reported in Newcomb , “Measures of the velocity of light made under direction of the Secretary of the Navy, 1880–82”, Astronomical papers of the American Ephemeris , ii (1891), 107–230. Vol. i of this series, begun by Newcomb, included Michelson's experimental determination of the velocity of light. That Newcomb wished to maintain some role is apparent in the fact that the Urgent Deficiency Act of 6 March 1882 provided “that the Superintendent of the Nautical Almanac be, and he is hereby, created an additional member of the said commission”. Horigan W. D. , “Memorandum for the Superintendent concerning the origin and operations of the U.S. Transit of Venus Commission”, 27 May 1927, U.S. Naval Observatory Library.

The most detailed statement on the work of Harkness is found in his own “Biographical memorandum” (ref. 9). On Harkness see also Nathan Reingold, “Harkness”, in Dictionary of scientific biography , vi (New York, 1972), 119, and the following obituaries: Frank Bigelow, Popular astronomy , xi (1903), 281–4; Publications of the Astronomical Society of the Pacific , xv (1903), 172–7; and Dugan R. S. , Dictionary of American biography 266. Because Harkness was never elected a member of the National Academy of Sciences (perhaps because of differences with Newcomb), there is no NAS Biographical Memoir. Harkness's published works are listed in vols vii, x and xv of the Catalogue of scientific papers compiled and published by the Royal Society. His largely mathematical photoheliograph paper is “Theory of the horizontal photoheliograph, including its application to the determination of the solar parallax by means of transits of Venus”, Monthly notices of the Royal Astronomical Society , xliii (1877), 129–55.

Harkness W. , “On the relative accuracy of different methods of determining the solar parallax”, American journal of science , xxii (1881), 375–94.

Harkness , “Address” (ref. 40), 87–88; Skinner , “William Harkness” (ref. 46), 604; Newcomb , Popular astronomy (ref. 3), 191.

Newcomb , Reminiscences (ref. 7), 173–4; AR (1885), 12; Sundry Civil Act, August 7, 1882, Statutes at large , xxii, 323. Correspondence related to the 1882 American transit of Venus observations is found in RG 78, E-18, Box 40, folder marked “Transit of Venus, 1882, September to December, 1882”. Unlike the 1874 correspondence, this consists largely of letters from the public asking for information about observing the transit.

Many of these reports are found in RG 78, E-18, Box 39, bound mss, including those from E. E. Barnard and others. At the age of 14, George Ellery Hale, later renowned for building the world's largest telescopes, made his first astronomical observations during the 1882 transit of Venus.

On the New Mexico party see Ponko Vincent Jr , “19th century science in New Mexico: The 1882 transit of Venus observations at Cerro Roblero”, Journal of the West , xxxiii (1994), 44–51. On the Florida party see Ponko Vincent Jr , “Cedar Key, Florida and the transit of Venus: The 1882 site observations”, Gulf Coast historical review , x (1995), 47–65. On the San Antonio party see Dick Steven J. , “The American Transit of Venus Expedition of 1882, including San Antonio”, Bulletin of the American Astronomical Society , xxvii (1995), 1331. On Newcomb's experiences see his Reminiscences (ref. 7). On his departure Newcomb left two iron pillars at the site of his observations, and entertained the “sentimental wish” that with the help of these markers the next transit of 2004 would be observed from the same site. However, by the 1930s the piers had disappeared, and in 1937 an iron post was erected to mark the site. (See “Astronomical relics at Touws River, C. P.”, South African journal of science , xxxiii (1937), 127–9.) Even this iron post no longer exists, but nevertheless there is a move afoot at the South African Astronomical Observatory to carry out Newcomb's wish by tracking down the exact site (Willie Koorts to Steven Dick J. , 21 July 1997). For further information on the 1882 expeditions, other than the Observatory annual reports cited below, recourse must be had to the Transit of Venus Commission archives, part of the records of the Naval Observatory, “Records of astronomical observations made chiefly in and near Washington, 1845–1907”, RG 78, entry 18, Boxes 1–55.

AR (1882), 117–19; AR (1883), 264–68. As it turned out, the latter report, and that of 1884, constitute the most detailed report published on the results of the American 1882 expeditions.

Harkness Tebbutt John , 27 Feb. 1891, in Horigan, “Memorandum” (ref. 45), 28; AR (1883), 267–8; AR (1884), 9–12; AR (1885), 12–13; AR (1886), 19; AR (1887), 15–17. The final result is given in AR (1888), 17–18, and AR (1889), 424–5. Among the personnel working on the reductions was Asaph Hall, Jr. The Legislative Act of 7 July 1884 provided $5000 for reductions.

“The solar parallax and its related constants”, Washington observations for 1885 (1891), Appendix III. Harkness also presented the result to the Philosophical Society of Washington on 13 October 1888.

Harkness W. , “On the magnitude of the solar system”, Astronomy and astro-physics , xiii (1894), 605–26.

“Memorandum concerning the printing of the Report upon the Observations of the Transits of Venus of 1874 and 1882”, typescript, Naval U.S. Observatory, 22 Dec. 1891. In 1896 Superintendent Pythian R. L. , together with the NAS President Wolcott Gibbs and Newcomb and Harkness, wrote a memorandum agreeing that the transit of Venus results should be published as appendices or supplements to the Washington observations, and thus at no expense to the Commission. This too did not happen. RG 78, E-18, Box 37, envelope marked “Authority for publishing transit of Venus observations in the Observatory volumes, April, 1896”.

Newcomb Simon , The elements of the four inner planets and the fundamental constants of astronomy (Washington, 1895), especially p. 157. On the controversial events leading to the introduction of Newcomb's constants, see Norberg Arthur L. , “Simon Newcomb's role in the astronomical revolution of the early nineteen hundreds”, in Dick Steven J. Doggett LeRoy (eds), Sky with ocean joined (Washington, 1983), 74–88.

Atkinson See R. d'E. , “The Eros parallax, 1930–31”, Journal for the history of astronomy , xiii (1982), 77–83.

Among the artifacts remaining at the Naval Observatory are several of the 5-inch refractors, transit instruments and photoheliographs. The latter were subsequently used for photographs of the Sun to measure sunspots. While most of the records are in the National Archives, the Naval Observatory Library still holds metal boxes marked with the name of each 1874 observing site, and containing some of the record books.

Harkness , “Address” (ref. 40), 77.