Your favor of the 24th was not recieved till the afternoon before your sons and nephew set out on their return. An earlier delivery would have gratified me by furnishing an opportunity of proving my esteem for you by my attentions to them. the same circumstance prevented my answering at the moment. I was glad to be informed by one of your sons that he expected to return to our university. As an encoragement to send him I can assure you that the Professors we recieved from abroad were of as happy a selection as could have been made. they are of the first order of science in their respective lines, correct in their characters and conduct, of amiable manners and dispositions, and full of zeal for the prosperity of their institution. I can add with confidence that a youth can now recieve here as high a degree of education, as solid and profound as in England. and why not? when they have recieved the highest there?

I have to thank you for the diagram of the Halo seen in Kentucky. these appearances, very common in high latitudes, are so rare in lower ones that I never heard but of a single one seen in this state. Capt Parry in his late voyage of discovery, saw them frequently where he wintered in latitude 76° I inclose you the diagrams of three, copied from his book, one of them nearly as complicated as yours. these phenomena proceed doubtless from combinations of reflection and refraction, their prismatic circles depending on the laws of the Solar rainbow, the white ones on those of the Lunar. the solar bow being single and simple is readily explained. but those of the Halo, from their numerous centres of relation, are not of so easy investigation it is singular that yours was twice seen over such an extent of country, and at times so distant.   I salute you with all the sincerity of antient friendship, & respect.

Th: Jefferson