DEAR SIR,--I am now to acknowledge the receipt of your favors of April the 14th, and June the 26th, as also of the second volume of the transactions you were so kind as to send me. It would have been a grateful present indeed, could you have accompanied them with a copy of your observations on our western country. Besides the interest I feel in that country in common with others, I have a particular one, as having ventured so many crudities on that subject. A copy of these, with some late corrections, I have put into a box of books sent to Mr. Madison, and another for Mr. Hopkinson. I hope he will forward them to you from New York. I have also put into the same box for you a dissertation, by De la Sauvagere, on the spontaneous growth of shells. When I was at Tours this summer, I inquired into the character of De la Sauvagere, from a gentleman who had known him well. He told me he was a person of talents, but of a heated imagination; however, that he might be depended on for any facts advanced on his own knowledge. This gentleman added, that he had seen such proofs of this growth of shells in many parts of the country round Tours, as to convince him of the truth of the fact; and that he has never seen any person, even the most incredulous, quit those Falunieres but under the same conviction. After all, I cannot say I give faith to it. It is so unlike the processes of nature, to produce the same effect in two different ways, that I can only bring myself to agree it is not impossible. I have added for you the Connoissance des Temps for '88 and '89, and a copy of Fourcroi's Chemistry, which is the best and most complete publication in that line, which we have had for some time past. I shall be happy to receive an account of your improvement in time-pieces, as well as the third volume of the transactions, when published. There are abundance of good things in the second volume. But I must say there are several which have not merit enough to be placed in such company. I think we should be a little rigid in our admission of papers. It is the peculiar privilege derived from our not being obliged to publish a volume in any fixed period of time. A person here pretends to have discovered the method of rendering sea-water potable, and has some respectable certificates of its success. He has contrived a varnish, also, for lining biscuit barrels, which preserves the biscuit good, and keeps it free from insects. He asks money for his secrets, so we are not to know them soon.