Rainbows over Monticello

[This is my letter to William Dunbar, dated January 12, 1801, where I discuss the many rainbows I observed at Monticello, even at night!]

I remark a rainbow of a great portion of the circle observed by you when on the line of demarcation. I live in a situation which has given me an opportunity of seeing more than the semicircle often. I am on a hill five hundred feet perpendicularly high. On the west side it breaks down abruptly to the base, where a river passes through. A rainbow, therefore, about sunset, plunges one of its legs down to the river, five hundred feet below the level of the eye on the top of the hill. I have twice seen bows formed by the moon. They were of the color of the common circle round the moon, and were very near, being within a few paces of me in both instances.