Having seen your Observations upon the late solar Eclipse, I took the Liberty to transmit a Copy of them to Mr W. Lambert, in Washington, & to request him to favour me with a Calculation of the Longitude of Monticello founded upon them. I now transmit his Paper, & hope it will prove agreable to you. The Facility & Accuracy of Mr L. in astronomical Calculation is very remarkable. This I have known for some Time past; & upon that Ground the application was made to him. Mr Blackburn, the Mathl Professor, is also a good Calculator; but he is so engaged that I know not when he will attempt a similar Deduction.

Mr Lambert’s Paper is drawn up more fully than may appear necessary; but it serves to test the Accuracy of the apparently different Rules given by celebrated Astronomers.

By my Observation upon the solar Eclipse of 1806, the End of which was accurately noted, & the Time well ascertained, Williamsburg is 5H 17′ 4″ from Paris 9′ 20″ by Greenwich,1 which compared with the Long. of Monticello, gives the strait-lined Distance, I beleive, very accurately, or rather nearly.