I have long deferred doing myself the honor of writing to you, wishing for an opportunity to accompany my letter with a copy of the _Bibliothèque Physico-oeconomique_, a book published here lately in four small volumes, and which gives an account of all the improvements in the arts which have been made for some years past. I flatter myself you will find in it many things agreeable and useful. I accompany it with the volumes of the _Connoissance des Terns_ for the years 1781, 1784, 1785, 1786, 1787. But why, you will ask, do I send you old almanacs, which are proverbially useless? Because, in these publications have appeared, from time to time, some of the most precious things in astronomy. I have searched out those particular volumes which might be valuable to you on this account. That of 1781 contains De la Caillie’s catalogue of fixed stars reduced to the commencement of that year, and a table of the aberrations and nutations of the principal stars. 1784 contains the same catalogue with the _nébuleuses_ of Messier. 1785 contains the famous catalogue of Flamsteed, with the positions of the stars reduced to the beginning of the year 1784, and which supersedes the use of that immense book. 1786 gives you Euler’s lunar tables corrected; and 1787, the tables for the planet Herschel. The two last needed not an apology, as not being within the description of old almanacs. It is fixed on grounds which scarcely admit a doubt, that the planet Herschel was seen by Mayer in the year 1756, and was considered by him as one of the zodiacal stars, and, as such, arranged in his catalogue, being the 964th which he describes. This 964th of Mayer has been since missing, and the calculations for the planet Herschel show that, it should have been, at the time of Mayer’s observation, where he places his 964th star. The volume of 1787 gives you Mayer’s catalogue of the zodiacal stars. The researches of the natural philosophers of Europe seem mostly in the field of chemistry, and here, principally, on the subjects of air and fire. The analysis of these two subjects presents to us very new ideas. When speaking of the _Bibliothèque Physico-oeconomique_, T should have observed, that since its publication, a man in this city has invented a method of moving a vessel on the water, by a machine worked within the vessel. I went to see it. He did not know himself the principle of his own invention. It is a screw with a very broad, thin worm, or rather it is a thin plate with its edge applied spirally round an axis. This being turned, operates on the air, as a screw does, and may be literally said to screw the vessel along: the thinness of the medium, and its want of resistance, occasion a loss of much of the force. The screw, I think, would be more effectual, if placed below the surface of the water. I very much suspect that a countrymen of ours, Mr. Bushnel of Connecticut, is entitled to the merit of a prior discovery of this use of the screw. I remember to