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.

The principal points in the geography of Asia, as given by Ptolemy, respect the coasts of India, the route to the Seres, and the Caspian sea.  His delineation of India is equally erroneous with his delineation of the British Isles:  according to him, it stretches in a right line from west to east, a little to the south of a line drawn between the Ganges and the Indus.  He possessed, however, information respecting places in the farther peninsula of India, the locality of several of which, by comparing his names with the Sanscrit, may be traced with considerable certainty.  He assigns to the island of Ceylon a very erroneous locality, arising from his error respecting the form of India, and likewise an extent far exceeding the truth.  He is the first author, however, who mentions the seven mouths of the Ganges.  The route to the Seres, which he describes, has been already noticed:  it is remarkable that the latitude which he assigns to his Sera metropolis, is within little more than a degree of the latitude of Pekin, which, in the opinion of Dr. Vincent, is one of the most illustrious approximations to truth that ancient