Some Aspects of American Astronomy 1750-1815

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  • Some Aspects of American Astronomy 1750-1815Author(s): John C. GreeneSource: Isis, Vol. 45, No. 4 (Dec., 1954), pp. 339-358Published by: The University of Chicago Press on behalf of The History of Science SocietyStable URL: .Accessed: 08/05/2014 23:03

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  • Some Aspects of

    American Astronomy i750-I8I5

    By John C. Greene *

    T HE purpose of the present essay is to describe some of the main directions of observation and inquiry in American astronomy in the late eighteenth

    and early nineteenth centuries and to show how these researches reflected or modified prevailing conceptions of nature. Certainly no science exerted a pro- founder influence on Western thought in this period than astronomy. What atomic physics is to our own century Newtonian astronomy was to the eighteenth. In Europe the best scientific minds vied with each other to extend and perfect Newton's mathematical demonstration of the solar system. To obtain the necessary data, expeditions were sent to the far corners of the earth - to Lapland, to the Cape of Good Hope, to South America and the South Seas.' These combined efforts reached a climax with the publication, in the years I798-I825, of Laplace's Mgcanique CUlhste, the summation of a century of progress in the astronomy of the solar system.

    To these brilliant achievements American astronomers contributed no great discoveries either empirical or theoretical, but they kept abreast of the latest developments, made and published useful observations, and propounded theo- ries of their own to account for what they observed. Astronomy was well established in the colonial colleges by the middle of the eighteenth century, especially at Harvard, where Professor John Winthrop continued with great ability the tradition of astronomical studies established at that institution in the seventeenth century. Appointed to the Hollis Professorship of Mathe- matics and Natural Philosophy in I738, Winthrop sent to England for a copy of Newton's Principia, introduced the study of fluxions, expanded the use of experiments in instruction, and began regular observation of the heavens with the college telescope. His most important observations were published in the

    *University of Wisconsin. 1Professor John Winthrop described to his

    class at Harvard some of the expeditions sent out to observe the transit of Venus in 176I: "The most Northern place the Transit was ob- serv'd at, was in EUROPE, namely, Tornea in Lapland; almost under the polar circle. -In ASIA, it was observed at Tobolsk, the capital of Siberia, by a French Astronomer, who per- formed a journey thither of 4000 miles from Paris, at the instance of the Imperial Academy of Sciences at Petersburg, and under the aus- pices of the Czarina. . . . It was observed be- sides at Madras, which was farthest South-east, under the direction of the East-India Company of London. The French King also commissioned two members of his Royal Academy of Sci-

    ences, to make the observation in the East Indies. -In AFRICA, it was observed only at the Cape of Good Hope. It would have been so at St. Helena too, had not clouds prevented, by Astronomers sent to those places by the Royal Society, at the expence of his late Majesty K. George II.... In AMERICA, it was ob- served only at St. John's Newfoundland, and that at the expence of the Province of Massa- chusetts-Bay. And this place was the farthest West." John Winthrop, Two Lectures on the Parallax and Distance of the Sun, as Deducible from the Transit of Venus (Boston, 1769), 39- 40. For a brief account of developments in astronomy in Europe in the eighteenth century see Peter Doig, A Concise History of Astronomy (London, I950), chs. 8".


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  • 340 JOHN C. GREENE

    Philosophical Transactions of the Royal Society, of which he was elected a Fellow in I766.2

    The other colonial colleges did their best to emulate Harvard's example. Yale acquired an able mathematician and college president in Thomas Clap two years after Winthrop's appointment at Harvard. William and Mary made her bid in I758 with the appointment of William Small to the post in natural philosophy. The College of Philadelphia had an astronomer of considerable talent in its first provost, the Reverend William Smith. After the Revolution it was not uncommon for college presidents to teach or study astronomy. Yale's Ezra Stiles was a lifelong student of the subject and a practicing observer. President Willard of Harvard corresponded with the Astronomer Royal in Britain and contributed several astronomical papers to the Memoirs of the American Academy of Arts and Sciences, which he had helped to found. On his death in I804 he was succeeded by the professor of mathematics and natural philosophy, Samuel Webber. Robert Patterson occupied the mathematical chair at the University of Pennsylvania, but the Provost, the Reverend John Ewing, was equally capable as a natural philosopher, having served with Ritten- house in surveying the boundaries of Pennsylvania. In the survey of the south- ern boundary, involving the extension of the Mason-Dixon line, they were joined by another college president versed in natural philosophy, the Reverend James Madison of William and Mary, one of the commissioners for the state of Virginia.3

    Not all American astronomers were academics, however. The two best known in the early republic, David Rittenhouse and Nathaniel Bowditch, were both self-educated. Bowditch pursued his studies aboard ship while voyaging the seas as a common sailor. He later combined his nautical and astronomical knowledge to produce the famous Practical Navigator. Then, settled at Salem as president of a fire and marine insurance company, he devoted his leisure hours to preparing a translation with commentary of Laplace's M!canique CMlAste. Rittenhouse earned the means to study mathematics and astronomy by making precision clocks. His ingenious orrery, or mechanical model of the solar system, fetched a handsome price, and his growing reputation in both practical and theoretical astronomy procured him work as a surveyor. Andrew

    ' John Winthrop and several other figures discussed here are treated more fully in the writings of Frederick E. Brasch: "Newton's First Critical Disciple in the American Colo- nies - John Winthrop," in Sir Isaac Newton, Z727-1927, a Bicentenary Evaluation of His Work (Baltimore, I928), 30I-338; "The New- tonian Epoch in the American Colonies (i68o- 1783)," Proc. Amer. Antiq. Soc., I949, 49: 314-332; "The Royal Society of London and Its Influence upon Scientific Thought in the American Colonies," The Scientific Monthly, 193I, 33: 336-355, 448-469; "John Winthrop," Publ. Astron. Soc. Pacific, I9I6, 28: I53-I70. Professor Samuel Eliot Morison discusses "The Harvard School of Astronomy in the Seven- teenth Century" in The New England Quarterly, I934, 7: 3-24. See also Samuel A. Mitchell,

    "Astronomy During the Early Years of the American Philosophical Society," Proc. Amer. Philos. Soc., I943, 86: I3-2I; I. Bernard Cohen, Some Early Tools of American Science... (Cambridge, Mass., I950), chs. i-3; Solon I. Bailey, The History and Work of Harvard Ob- servatory 1839 to 1927 . . . (New York and London, I93I), ch. i; Theodore Hornberger, Scientific Thought in the American Colleges, z638-z800 (Austin, Texas, I945), ch. 5.

    8On the early history of science at Yale, see Louis W. McKeehan, Yale Science The First Hundred Years (New York, I947). Horace W. Smith, Life and Correspondence of the Rev. William Smith . . . (2 vols., Philadelphia, i88o) contains scattered materials on the astronomical interests and activities of the first provost of the College of Philadelphia. See also the works cited in the note above.

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    Ellicott lived chiefly by surveying. He assisted Rittenhouse in running the southern, western, and northern boundaries of Pennsylvania; then, in I79I, he surveyed the tract for the new capital on the Potomac, aided by the Negro astronomer and almanac-maker, Benjamin Banneker. His most arduous sur- vey was performed in the years I797-I800, as commissioner to run the south- ern boundary of the United States according to the terms of the Pinckney- Godoy Treaty of I796. One of the Spanish commissioners in the early stages of this survey was William Dunbar, gentleman planter of the Mississippi Terri- tory and a scientist of no mean ability. But Dunbar returned to his estate near Natchez when the western end of the line had been fixed, and Ellicott was left to carry the line eastward through swamp and forest to the Atlantic coast. "It is to be presumed," wrote Ellicott in his account of this survey, "that no apology will be necessary, for any small inaccuracies which may be discovered in the astronomical observations, when it is considered that they were made at temporary stations, and the apparatus frequently exposed to the weather, for want of tents, and other covering; and almost as frequently so injured by the transportation from one place, to another, through the wilderness, that if I had not been in the habit of constructing, and making instruments for my own use, our business must have several times suspended, till the repairs could have been made in Europe." 4

    Until just before the Revolution, American astronomers had to depend on European journals for publication of their findings. In I77I, however, the American Philosophical Society began publication of its Transactions. The New Englanders, not to be outdone by Philadelphia, organized the American Academy of Arts and Sciences, which brought forth its first Memoirs in I785. Observations of the transits of Mercury and Venus, of solar and lunar eclipses, of comets and meteors, as well as routine observations in the course of boundary surveys, occupied a prominent place in both publications. To these researches of American astronomers and to the speculations and reflections which they evoked we now turn.

    1. Transits and Eclipses

    Many of the astronomical papers published by Americans in these early years reported observations of transits and eclipses. The transits of Venus were of especial interest for reasons which Professor Winthrop explained to his students at Harvard in I 769:

    A TRANSIT OF VENUS UNDER THE SUN is the most uncommon, and the most important phaenomenon, that the whole compass of astronomy affords

    ' Andrew Ellicott, The Journal of Andrew Ellicott, Late Commissioner on Behalf of the United States . . .for Determining the Bound- ary Between the United States and the Posses- sions of His Catholic Majesty in America . . . (Philadelphia, I8I4), I5I. For biographical ma- terial see Catherine Mathews, Andrew Ellicott, His Life and Letters (New York, igo8); Ed- ward Ford, David Rittenhouse, Astronomer-

    Patriot z732-z796 (Philadelphia, I946); Robert E. Berry, Yankee Stargazer, The Life of Na- thaniel Bowditch (New York and London, I94I); Mrs. Dunbar Rowland, comp., Life, Letters and Papers of William Dunbar of Elgin, Morayshire, Scotland, and Natchez, Mississippi, Pioneer Scientist of the Southern United States (Jackson, Mississippi, I930); Shirley Graham, Your Most Humble Servant [Benjamin Ban- neker] (New York, I949).

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  • 342 JOHN C. GREENE

    us. So uncommon is it, that it can never happen above twice in any century; in others, but once; and in some centuries it cannot happen at all. And the im- portance of it is such, as to supply us with a certain and complete solution of a very curious Problem, which is inaccessible any other way....

    It is plain enough, that our hopes of finding the distances of the heavenly bodies, with any certainty, must be built on observations of their parallaxes. If the diameter of the Earth bear any sensible proportion to the distance of an heavenly body, that body must be subject to a parallax, of some quantity or other; that is, it must appear in different points of the starry heaven, when view'd from different parts of the Earth. . . . Venus in her inferior conjunction is but little more than one quarter so far from us as the Sun is, and therefore her parallax almost four times as great as his. This therefore is the most ad- vantageous circumstance. But a Transit of Venus is the most favorable con- juncture of all, because the limbs of the Sun afford the best terms with which to compare the planet; and instead of trying to observe the parallactic angles, which are extremely small, it is much better to observe the differences of time, occasion'd by them, which are much more sensible. . . The best observations will be, when the planet is in contact with the Sun's limbs, at its immersion and emersion; the moments of which may be determined with great accuracy, if the air be clear, by such as are furnished with good astronomical instruments, and are expert in the use of them.5

    Winthrop could speak with authority on this subject, for he was an old hand at observing transits. Two of his earliest communications to the Royal Society concerned transits of Mercury, and in I76I he had organized and carried through an expedition to Newfoundland for the purpose of observing the transit of Venus. The governor and legislature of Massachusetts Bay were apprised of the fact that astronomers had been looking forward to this event with great anticipation and that royal support had been secured in England and France for expeditions to the remo...


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