MERCATOR, ORTELIUS, AND THEIR SUCCESSORS 111 



the Flemish cartographers Ortelius and Mercator who, in 

 addition to their other achievements, met in a practical way 

 the public demand for a comprehensive, up-to-date, and 

 convenient collection of maps, by inaugurating the long 

 series of modern atlases. 



Gerhard Mercator (the Latinized form of his surname, 

 Kremer), born at Rupelmonde in Flanders in 1512, owed much 

 to his relations with Gemma Phrysius, the cosmographer and 

 editor of Peter Apian. As a pupil of Gemma's at the University 

 of Louvain, Mercator showed himself to have an aptitude 

 for practical tasks. He is first mentioned as the engraver for 

 the gores of Gemma's globe of about 1536; he was also a maker 

 of mathematical and astronomical instruments, and in his 

 early days a land surveyor. It was no doubt this aptitude that 

 led him later to examine and to solve the problem of concern 

 to the practical navigator, namely the representation of constant 

 bearings (loxodromes) as straight lines on a chart. In the course 

 of his long life, he also acquired a profound knowledge of 

 cosmography and of topographical progress in Europe and 

 beyond, and won general recognition as the most learned 

 geographer of his day. While at Louvain, he established him- 

 self as an authority on all these matters in the intimate circle 

 of the Emperor Charles V, a position which, in particular, 

 brought him into contact with the navigators and cartographers 

 of Portugal and Spain, then in the van of progress in these 

 sciences. His principal achievements were his globe of 1541 and 

 his celebrated world map of 1569; his large map of Europe of 

 1554; his edition of Ptolemy, 1578, and his Atlas, still in 

 course of publication at his death in 1594. 



The practical seaman of the day required a chart on which 

 a line of constant bearing could be laid down as a straight line. 

 This was impossible on contemporary charts, which made no 

 allowance for the convergence of the meridians. If a line is to 

 preserve a constant bearing on the globe it must cut each 

 meridian at the given angle. Since the meridians converge on 

 the Pole, this line clearly becomes a spiral, circling closer and 

 closer to the Pole, but theoretically never reaching it. On his 

 globe of 1541, on which for the first time these loxodromes 

 were laid down, Mercator put them in by means of a simple 



