The matter of the ensuing essay may be regarded as two-fold. First, we undertake to vindicate the chronology of Ptolemy's Canon for the first 212 years of that table of reigns at Babylon; that is to say, from the first of Nabonassar to the third year of the nine which the table gives to Cyrus. Next, we propose to show that Nineveh was taken, and, with that capital, the proper Assyrian empire was overthrown, by the Babylonians and Medes, iu the year B.C. 608. In connection with this latter subject are treated several important historical topics; the expeditions of Nekho, king of Egypt, first, in B.C. 609, against the falling Assyrian, and, secondly, in B.C. 605, against the growing Babylonian power; the complete establishment of the Babylonian supremacy by Nebukhadrezzar, in the years from B.C. 606 to B.C. 604; the true relationship, unconsciously attested by Herodotus, between the Medes and the Scythians for twenty-eight years; that is, as will be shown, for twenty-two years before and for six years after the fall of Nineveh; the true dimensions of the war which, according to Herodotus, Cyaxares, king of the Medes, waged with Alyattes, king of the Lydians; the entire trustworthiness of Herodotus's Median chronology; and, a criticism showing the probable Herodotean date of the conquest of Crcesus and his Lydians by the Medes under Cyrus the Persian.