I have enclosed the first 12 pages of my astronomical observations:—you will perceive they are intended as an appendix to another work, and which I fear, I shall not be able to put to the press in less than six, or seven months.—I began with the observations at this time, to make the trouble as little as possible, both to the printer, who is now at work upon the fifth volume of our transactions (in which they will appear) and to myself.—You will find the observations much more numerous than you expect;—the printer informs me that they will not occupy less than 150 or 160 pages.—there are certainly four, or five times as many, as were ever made by an individual in the same time, situated as I was.—The calculations were a work of great labour, and in which I had no assistance, and could derive none from any of the party except Mr. Dunbar, who was with us but a short time, and to whose uncommon talents I have endeavoured to do justice.—If you have no objection, I will forward the subsequent sheets as they are worked off, and if you should find any amusement in looking over them, I shall esteem it a singular favour if you would point out any material errors, that they may be corrected in the last sheet.

I have received your note of the 13th., and return you my most cordial thanks for the interest you have taken in my business, and as soon as the printer gets thro’ with the observations, I shall repair to the City of Washington.—

I am sir with sincere esteem and regard your friend & Hl. Servt