Having offered these general remarks on the excellencies and errors of Ptolemy, we shall next proceed to give a short and rapid sketch of his geographical knowledge respecting Europe, Asia, and Africa. On the north-east of Europe he gives an accurate description of the course of the Wolga; and further to the south, he lays down the course of the Tanais, much nearer what it really is than the course assigned it by Strabo. He seems to have been acquainted with the southern shores of the Baltic from the western Dwina, or the Vistula, to the Cimbric Chersonesus: he also describes part of the present Livonia. The Chersonesus, however, he stretches two degrees too far to the north, and also gives it too great a bend to the east. He applies the name of Thule to a country situated to the north-east of Britain; if his usual error in longitude is rectified, the position he assigns Thule would correspond with that of Norway. Such seem to have been the limits of his Europe, unless, perhaps, he had some vague idea of the south of Sweden. He begins his geographical tables with the British isles; and here is one of his greatest errors. According to him, the north part of Britain stretches to the east, instead of to the north: the Mull of Galloway is the most northern promontory, and the land from it bends due east. The Western Islands run east and west, along the north shore of Ireland, the west being the true north point in them. He is, however, on the whole, pretty accurate in his location of the tribes which at that period inhabited Scotland. Strabo had placed Ireland to the north of Britain, but in its true latitude. Ptolemy's map, which is the first geographical document of that island, represents it to the west of Britain, but five degrees further to the north than it actually is. He delineates its general shape, rivers, and promontories with tolerable accuracy, and some of his towns may be traced in their present appellations, as Dublin in Eblana. It has already been noticed that he was probably acquainted with the south of Sweden, and his four Scandinavian islands are evidently Zealand, Funen, Laland, and Falster. It is remarkable that his geography is more accurate almost in proportion as it recedes from the Mediterranean. The form which he assigns to Italy is much farther removed from the truth than the form of most of the other European countries which he describes. His fundamental error in longitude led him to give to the Mediterranean Sea a much greater extent than it actually possesses. According to him, it occupies nearly sixty-five degrees; and it is a singular circumstance, as well as a decisive proof of the influence of his authority, as well of the slow progress of accurate and experimental geography, that his mensuration of this sea was reputed as exact till the reign of Louis XIV., when it was curtailed of nearly twenty-five degrees by observation.