MAPS AND MAP-MAKING BEFORE MERC AT OR. 483 



from other sources. With Eratosthenes, who died about the begin- 

 nino- of the second century before Christ, the science of geography- 

 may be said to have begun. He was the first to apply a purely scien- 

 tific method to ascertain the magnitude of the earth ; for, when a 

 knowledo-e of the exact circumference of the globe was once obtained, 

 the different countries and places could be arranged in these ancient 

 maps, in their relative position to each other, far more accurately. 

 The distances between places in what was then known as the inhabited 

 part of the earth were previously ascertained by the number of days it 

 took to go from one place to another, derived from the information of 

 travelers and mariners. 



To rectify the errors which became more apparent and confusing 

 as the inhabited part of the world became better known, Eratosthenes 

 devised, what has ever since been employed as the most accurate means 

 of determining the circumference of the earth, the measurement of an 

 arc of the meridian. He found a confirmation of the globular form of 

 the earth in the fact that at Syene, in Upper Egypt, upon the tropic, 

 the sun at noon on the day of the summer solstice was vertical — that 

 is, that it cast no shadow, a well at the bottom being enlightened by its 

 rays ; while at Alexandria, upon the same day and time, it was distant 

 from the zenith one fiftieth of the circumference of the circle. Era- 

 tosthenes obtained by this means the length of what is called an arc of 

 the meridian, or a portion of the curved surface of the earth ; and 

 from this he was able, by a familiar rule, to determine the circumfer- 

 ence of the whole circle. 



The happy idea occurred to Hipparchus of applying to the earth 

 the same method he had used in fixing the position of the stars in the 

 celestial sphere. Regarding the earth as a great circle, which, like any 

 other circle, is divisible into three hundred and sixty degrees, he so 

 divided it, by lines of circles drawn pei-pendicularly from the poles to 

 the equator, and by parallel lines at equal distances from the equator 

 to the poles, which was the beginning of the division of the globe by 

 lines of longitude and latitude into degrees. 



The Romans, in their representation of the earth, at first followed 

 Eratosthenes and Hipparchus, The Emperor Augustus ordered the 

 geographers and designers to prepare for the use of the people a map 

 of the habitable world which should represent fully the extent of the 

 Roman Empire ; and, from some fragments that were preserved, it 

 is known that this map was a cylindrical projection of a great circle. 

 The Romans, however, had a map for practical use, w^hich they styled 

 a descrij^tive itinerary, or, as they sometimes called it, "painted roads.'''' 

 This map was in the form of a band, about a foot wide and about 

 twenty feet long, upon which the habitable earth was continuously 

 represented along parallel spaces. It represented pictorially the great 

 routes or roads of the empire, the position of places with the dis- 

 tances between them, the ranges of mountains, and the direction of 



