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Thomas Jefferson to John Payne Todd, 10 October 1811

To John Payne Todd

Monticello Oct. 10. 11.

Dear Sir

According to promise I send you our observations of the solar eclipse of Sep. 17. we had, you know, a perfect observation of the passage of the sun over the meridian, and the eclipse began so soon after as to leave little room for error from the time piece. her rate of going however was ascertained by 10. days subsequent observation and comparison with the sun, and the times, as I now give them to you are corrected by these. I have no confidence in the times of the 1st & ultimate contacts, because you know we were not early enough on the watch, decieved by our time piece which was too slow. the impression on the sun was too sensible when we first observed it, to be considered as the moment of commencement, and the largeness of our conjectural correction (18″) shews that that part of the observation should be considered as nothing. the last contact was well enough observed, but it is on the forming and breaking of the annulus that I rely with entire confidence. I am certain there was not an error of an instant of time in either. I would be governed therefore solely by them, and not suffer their result to be affected by the others. I have not yet entered on the calculation of our longitude from them. they will enable you to do it as a college exercise. affectionately yours

Th: Jefferson

1st contact 0– 13– 54 }
annulus formed 1– 53– 0 } central time  H     central time H    
annulus broken 1– 59– 25 of annulus. 1–56–12½ of the two contacts  1–51–28
ultimate contact 3– 29– 2

Latitude of Monticello 38°–8′

RC (NjMoHP: Lloyd W. Smith Collection); at foot of text: “Mr Paine Todd.” PoC (DLC).

John Payne Todd (1792–1852) was the only child to survive infancy of Dolley Payne Todd Madison and her first husband, John Todd. He attended Saint Mary’s College in Baltimore from 1805 until 1812. Todd served briefly as his stepfather James Madison’s secretary early in 1813, and in the spring of that year he joined Albert Gallatin’s diplomatic mission to Russia. During his European travels Todd began a lifelong pattern of dissipation. He drank and gambled heavily and amassed huge debts after returning to the United States in 1815. Madison paid Todd’s creditors some $40,000 between 1813 and his own death in 1836, but Todd was still imprisoned for debt on several occasions. In his will the unmarried Todd directed that his slaves be freed and given $200 each, and he left the residue of his estate to the American Colonization Society. Given the extent of his debts, the bequests were probably not honored (Dolley Madison, Selected Letters description begins David B. Mattern and Holly C. Shulman, eds., The Selected Letters of Dolley Payne Madison, 2003 description ends , esp. 219–20, 325–6, 414; Ralph Ketcham, James Madison: A Biography [1971; repr. 1990], 552, 601, 615–6; Madison, Papers description begins William T. Hutchinson, Robert A. Rutland, John C. A. Stagg, and others, eds., The Papers of James Madison, 1962– , 29 vols.: Congress. Ser., 17 vols.; Pres. Ser., 5 vols.; Sec. of State Ser., 7 vols description ends , Pres. Ser., 2:370–2, 4:444; Orange Co. Will Book, 11:476–8, 12:18–20).

During an annular eclipse the moon passes directly in front of the sun, leaving a ring of light, the annulus (OED description begins James A. H. Murray, J. A. Simpson, E. S. C. Weiner, and others, eds., The Oxford English Dictionary, 2d ed., 1989, 20 vols. description ends ).

Index Entries

  • astronomy; and solar observations search
  • clocks; and solar eclipse search
  • geography; and TJ’s calculations of latitude search
  • Monticello (TJ’s estate); solar eclipse observed by TJ at search
  • sun; annular eclipse of1811observed search
  • Todd, John Payne; and TJ’s observations of solar eclipse search
  • Todd, John Payne; identified search
  • Todd, John Payne; letters to search