Your favor of Oct. 14. was duly recieved, and with it mr Bowditch’s observations on the comet, for which I pray you to accept my thanks, and to be so good as to present them to mr Bowditch also. I am much pleased to find that we have so able a person engaged in observing the path of this great phaenomenon; and hope that from his observations & those of others of our philosophical citizens on it’s orbit we shall have ascertained, on this side of the Atlantic, whether it be one of those which have heretofore visited us. on the other side of the water they have great advantages in their well established Observatories, the magnificent instruments provided for them, and the leisure & information of their scientific men. the acquirements of mr Bowditch in solitude & unaided by these advantages do him great honor:

With respect to the eclipse of Sep. 17. I know of no observations made in this state but my own, altho’ I have no doubt that others have observed it. I used myself an Equatorial telescope, & was aided by a friend, who happened to be with me, and observed thro’ an achromatic telescope of Dollond’s. two others attended the timepieces.1 I had a perfect observation of the passage of the sun over the meridian, and the eclipse commencing but a few minutes after, left little room for error in our time. this little was corrected by the known rate of going of the clock. but we as good as lost the first appulse by a want of sufficiently early attention to be at our places, & composed. I have no confidence therefore, by several seconds, in the time noted. the last osculation of the two luminaries was better observed.2 yet even there was a certain term of uncertainty as to the precise moment at which the indenture on the limb of the sun entirely3 evanished. it is therefore the forming of the annulus, & it’s breaking, which alone possess my entire & compleat confidence. I am certain there was not an error of an instant of time in the observation of either of them. their result therefore should not be suffered to be affected by either of the others. the four observations were as follows.4

	H ′ ″
The 1st appulse	0–13–54		—————————
annulus formed	1–53– 0		central time of		central time of the
annulus broken	1–59–25		annulus 1 H–56′–12½″		two5 contacts 1 H–51′–28″
last osculation	3–29– 26		—————————

Latitude7 of Monticello 38°–8′

I have thus given you, Sir, my observations, with a candid statement of their imperfections. if they can be of any use to mr Bowditch, it will be more than was in view when they were made; and should I hear of any other observations made in this state, I shall not fail to procure & send him a copy of them. be so good as to present me affectionately to your much esteemed father, & to accept the tender of my respect.

Th: Jefferson