Tuttle: Historic Maps of Staten Island 71 



of Spain offered i,oo'o crowns in 1598, the States General follow- 

 ing with an offer of 10,000 florins. It was expected at this time- 

 that longitude would be determined by the variation of the needle, 

 which appeared to increase with regularity to the westward. One 

 will observe that Hudson and other navigators" of this time 

 measured the variation of the needle quite frequently. The 

 determination of longitude by lunar distance required more 

 accurate tables of the' moon than were in existence at the time,. 

 and a more accurate instrument than the cross staff with which 

 to make the angular measurements. It was not until 1675 that 

 the Greenwich observatory was established to advance nautical 

 science, and not until 1731 that the. sextant was invented. The- 

 improvement in the lunar tables so as to make them serviceable 

 in longitude determinations was not effected until 1753, and'. 

 Harrison's chronometer was not invented until 1761. Latitudes 

 were therefore given on maps previous to about 1760 much more 

 accurately than longitudes, which on account of their uncertainty 

 were frequently omitted. Latitude and longitude, as we under- . 

 stand them, had been used by Europeans in map making 

 for only about a century. The production of maps and charts 

 had received a considerable impetus from the great amount of 

 exploration, and some great advances had only recently been 

 made in the projection of charts by Mercator, one of the earliest 

 of modern cartographers. The Dutch led in these improvements 

 as the result of the work of Mercator, Ortelius, and Hondius. 

 The nautical maps in which the Dutch excelled at the beginning- 

 of the seventeenth century are called loxodromic or compass 

 maps, because the courses of ships were plotted a's straight lines, 

 and distant shores were located from the courses and distances 

 run by individual ships. At this time when so many compass 

 lines were drawn from several points on a map, parallel rules 

 were not in use, and the course of a ship was traced on a chart 

 by placing one leg of a pair of compasses on the starting point 

 and the other leg on a line which came nearest in direction to 

 the course sailed. This leg was moved forward along the line- 



