My full conviction respecting the nature and origin of the enchorial character I expressed at the end of a collection of letters, inserted in the MUSEUM CRITICUM, and published in 1815. It was not, however, till the next year, that I obtained the most complete evidence of the truth of my opinion: having been obligingly accommodated, by Mr. William Hamilton, with the use of his copy of the great _Description de l’Égypte_, as far as it was then published, I proceeded to study its contents: and I discovered, at length, that several of the manuscripts on papyrus, which had been carefully published in that work, exhibited very frequently the same text in different forms, deviating more or less from the perfect resemblance of the objects intended to be delineated, till they became, in many cases, mere lines and curves, and dashes and flourishes; but still answering, character for character, to the hieroglyphical or hieratic writing of the same chapters, found in other manuscripts, and of which the identity was sufficiently indicated, besides this coincidence, by the similarity of the larger tablets, or pictural representations, at the head of each chapter or column, which are almost universally found on the margins of manuscripts of a mythological nature. And the enchorial inscription of the pillar of Rosetta resembled very accurately, in its general appearance, the most unpicturesque of these manuscripts. It did not, however, by any means agree, character for character, with the “sacred letters” of the first inscription, though in many instances, by means of some intermediate steps derived from the manuscripts on papyrus, the characters could be traced into each other with sufficient accuracy, to supersede every idea of any essential diversity in the principles of representation employed. The want of a more perfect correspondence could only be explained, by considering the sacred characters as the remains of a more ancient and solemn mode of expression, which had been superseded, in common life, by other words and phrases; and, in several cases, it seemed probable, that the forms of the characters had been so far degraded and confused, that the addition of a greater number of distinguishing epithets had become necessary, in order that the sense might be rendered intelligible. A particular account of this comparison of the different modes of writing, and a detailed reference to the passages of the respective manuscripts from which they were derived, is contained in two letters, printed in 1816, as a part of the seventh number of the Museum Criticum, and of which several copies were immediately sent to Paris, and to other parts of the Continent, although the actual publication of the number was retarded till 1821.