August 22, 1801 | Letter William Dunbar to Thomas Jefferson, August 22, 1801 William Dunbar writes to Thomas Jefferson of scientific matters, including the properties of rainbows. Dunbar anticipates fossil finds west of the Mississippi River, based on information forwarded by the late Philip Nolan. This letter, with several other missives and reports written by Dunbar, were forward by Jefferson to the American Philosphical Society, where they were read before the Society and later published in theTransactions of the Philosophical Society of Americain 1809. See the "Reports" section of this archive.