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 Such being the configuration of the whole earth, it will be convenient to take two straight lines, cutting each other at right angles, and running the one through its greatest length, and the other through its breadth. The former of these lines will represent one of the parallels, and the latter one of the meridians.1 Afterwards we must imagine other lines parallel to either of these respectively, and dividing both the land and sea with which we are acquainted. By this means the form of the habitable earth will appear more clearly to be such as we have described it; likewise the extent of the various lines, whether traced through its length or breadth, and the latitudes [of places], will also be more clearly distinguished, whether north or south, as also [the longitudes] whether east or west. However, these right lines should be drawn through places that are known. Two have already been thus fixed upon, I mean the two middle [lines] running through its length and breadth, which have been already explained, and by means of these the others may easily be determined. These lines will serve us as marks to distinguish countries situated under the same parallel, and otherwise to determine different positions both in respect to the other portions of the earth, and also of the celestial appearances.
1 We have long had the custom of tracing on every map the parallels of latitude and longitude at every degree, or every five or ten degrees, as the case may be. By means of these lines drawn at equal distances, the eye at once recognises the relative position of any place in the map. This method was not in use when Strabo wrote: at that time it was customary to draw a meridian or longitude, and a parallel of latitude, for every important place of which the position was considered as determined. This was certainly an obscure way of dividing the globe; nevertheless it is requisite to keep it in mind, in order that we may the more readily understand the general language of our geographer, who instead of simply stating the latitude and longitude of places, says such a place is situated under the same latitude, or about the same latitude, as such another place, &c. Ptolemy seems to have been the first who freed the study of geography from the confusion inseparable from the ancient method. He substituted tables easy of construction and amendment; where the position of each place was marked by isolated numbers, which denoted the exact latitude and longitude.
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