Descriptions or γῆς περίοδοι of this kind probably existed in Greece in great numbers; they were written in a lively manner to afford entertainment, and for such persons as wished to gain information about the earth and its inhabitants. But there also existed another kind of descriptions intended for the practical guidance of merchants and sailors; these men who had no ambition to investigate the interior of countries, could not but feel an interest in the descriptions of the coasts. As navigation was chiefly coasting, the want of such descriptions was felt, men being anxious to know in what manner town followed after town, harbour after harbour, and promontory after promontory. These are the περίπλοι: the most ancient is that by Scylax of Caryanda, a contemporary of Philip of Macedonia, as I have shewn by incontrovertible arguments[3]. Besides this description of the Mediterranean, there were others of the Euxine and the Erythraean Sea, which were composed at a much later period. Throughout the middle ages, these and similar περίπλοι were used, and the modern Greeks still have guides similar to those of their ancestors of old. Even till very recent times, sailors who confined themselves to the navigation of the Mediterranean, made use of what are called _Portolani del Mare_, which, previously to the invention of printing, were circulated in manuscript. The ancients accordingly had two kinds of materials, descriptions of coasts and descriptions of countries. After the time of Hecataeus, 150 years passed away before a real geography was written by Eratosthenes, whose object was to furnish a scientific chorography. In Herodotus chorography and history are combined, both are equally his object. He rarely combats Hecataeus, and not by name, but he often attacks his system, being conscious that he can give more accurate information. His work shows us the limits of the science in his time.