In the large irregular-shaped box, a tusk of large size. The spiral twist in all the specimens of these tusks which we have seen, was remarked so long ago as the time of Breyneus, in his description of the tusks of the Siberian mammoth in the Philosophical Transactions, if that paper is rightly recollected, for the book is not here to be turned to at present. Many fragments of tusks have been sent from the Ohio, generally resembling portions of such tusks as are brought to us in the course of commerce. But of these spiral tusks, in a tolerable complete state, we have had only four. One was found near the head of the north branch of the Susquehanna. A second possessed by Mr. Peale, was found with the skeleton, near the Hudson. A third is at Monticello, found with the bones of this collection at the Big-bone lick of Ohio, and the fourth is that now sent for the Institute, found at the same place and larger than that at Monticello. The smallest box contains the horns of the mountain ram, and skin of the fleecy goat. TO MR. SYLVESTRE. WASHINGTON, July 15, 1808. SIR,--I had received from you on a former occasion the four first volumes of the Memoirs of the Agricultural Society of the Seine, and since that, your letter of September 19th, with the 6th, 7th, 8th, and 9th volumes, being for the years 1804 '5 '6 with some separate memoirs. These I have read with great avidity and satisfaction, and now return you my thanks for them. But I owe particular acknowledgments for the valuable present of the Theatre de De Serres, which I consider as a prodigy for the age in which it was composed, and shows an advancement in the science of agriculture which I had never suspected to have belonged to that time. Brought down to the present day by the very valuable notes added, it is really such a treasure of agricultural knowledge, as has not before been offered to the world in a single work. It is not merely for myself, but for my country, that I must do homage to the philanthropy of the Society, which has dictated their destination for me of their newly-improved plough. I shall certainly so use it as to answer their liberal views, by making the opportunities of profiting by it as general as possible.