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THE POPULAR SCIENCE MONTHLY. 



what was supposed to be their true position. In none of these early 

 maps is there any attempt to give in curved lines the form of conti- 

 nents, or to indicate the boundaries of countries. 



About the middle of the twelfth century, Roger, King of Sicily, 

 determined to have a map of the world constructed from the best in- 



FiG. 9.— Italian Itinerary, Thirteenth Century. 



formation that could then be obtained. For this purpose he sent intel- 

 ligent men to various parts of the known world, to take the latitude 

 and longitude of places, to collect itineraries, and gather every kind 

 of information that was desirable. Fifteen years were spent in this 

 preparatory work, and what had thus been obtained was intrusted to 

 Edrisi, an Arabian geographer and traveler, who had been invited to 

 the King's court, and from these materials Edrisi compiled a general 

 map, which was engraved upon a round table, or globe of silver. In a 

 manuscript in the National Library of Paris there are sixty-nine maps, 

 supposed to have been copied from this silver globe, and there is a 

 general copy of the map attached to a manuscript in the Bodleian Li- 

 brary at Oxford, This work of Edrisi was superior to anything that 

 had preceded it in the middle ages. It appears to have given a new 

 impulse to geographical inquiries, as it was compiled chiefly from the 

 new materials that had been obtained ; for Edrisi, upon examining the 

 works of his Arabic predecessors and the work of Ptolemy, found 

 that they had involved the general subject of geography in such doubt, 

 uncertainty, and confusion, that in constructing his map he rejected 

 them altogether as sources of authority. Edrisi also composed a geo- 

 graphical work which has survived. Wherever in it he had to refer 

 to the fabulous and impossible things asserted by his predecessors, he 

 generally accompanied the statement with the formula, " God only 

 knows how this is." 



To understand more clearly the rapid progress which was made in 



