Fig. 60. Portraits of Gerhard Mercator and Jodocus Hondius.
In Gemma Frisius, an eminent professor of mathematics in the University of Louvain, and at one time a pupil of Apianus, he appears, as before noted, to have found a sympathetic friend and counselor.[263] It probably was Frisius who suggested a career for the young scientist, since we find him, shortly after graduation, turning his attention to the manufacture of mathematical instruments, to the drawing, engraving, and coloring of maps and charts, wherein he found a vocation for the remainder of his life. In 1537 his first publication, a map of Palestine, appeared, to which he gave the title “Amplissima Terrae Sanctae descriptio.”[264] Immediately thereafter, at the instance of a certain Flemish merchant, he undertook the preparation of a map of Flanders, making for the same extensive original surveys. This map was issued in the year 1540.[265] Mercator’s first published map of the world bears the date 1538. This map was drawn in the double cordiform projection which seems first to have been employed by Orontius Finaeus in his world map of 1531.[266] In this map Mercator departed from the geographical notions generally entertained at this particular period which made America an extension of Asia. He represented the continent of Asia separated from the continent of America by a narrow sea, an idea which increased in favor with geographers and cartographers long before actual discovery proved this to be a fact. This map is one to which great importance attaches, but it is not the first world map on which there was an attempt to fasten the name America upon both the northern and the southern continents of the New World, although it frequently has been referred to as such; this honor, so far as we at present know, belongs to a globe map referred to and briefly described above.[267] His large map of Europe, the draughting of which appears to have claimed much of his time for a number of years, was published in the year 1554, and contributed greatly to his fame as a cartographer.[268] In 1564 appeared his large map of England,[269] and in the same year his map of Lorraine based upon his own original surveys.[270] In the year 1569 a master work was issued, this being his nautical chart, “ad usum navigantium,” as he said of it, based upon a new projection which he had invented.[271] It is the original chart setting forth the Mercator projection which is now so extensively employed in map making. In the year 1578 he issued his revised edition of the so-called Ptolemy maps, and eight years later these same maps again, revised with the complete text of Ptolemy’s work on geography. Mercator expressly stated it to be his purpose, in this last work, not to revise the text in order to make it conform to the most recent discoveries and geographical ideas, but the rather to have a text conforming, as nearly as possible, to Ptolemy’s original work. This edition still ranks as one of the best which has ever been issued. His great work, usually referred to as his ‘Atlas of Modern Geography,’ the first part of which appeared in 1585, and a second part in 1590, was not completed during his lifetime, though but four months after his death, in the year 1594, Rumold Mercator published his father’s collection of maps, adding a third part to those which previously had been issued. It was this publication which bore the title ‘Atlas sive cosmographicae meditationes de fabrica mundi et fabricati figura.’ Apparently for the first time the term “atlas” had here been employed for a collection of maps, a term which we know had its origin with Gerhard Mercator himself. A reference to his general cartographical work more detailed than the above cannot here find place. It is his globes which call for special consideration.
There is reason for thinking it was Nicolás Perrenot, father of Cardinal Granvella, who suggested to Mercator the construction of a globe; it at least was to this great Prime Minister of the Emperor Charles V that he dedicated his first work of this character, a terrestrial globe dated 1541.[272] That Mercator had constructed such a globe had long been known through a reference in Ghymmius’ biography, yet it had been thought, until 1868, that none of the copies of this work had come down to us. In that year there was offered for sale, in the city of Ghent, the library of M. Benoni-Verelst and among its treasures was a copy of Mercator’s engraved globe gores of the year 1541, which were acquired by the Royal Library of Brussels, where they may still be found. Soon thereafter other copies of these gores, mounted and unmounted, came to light in Paris, in Vienna, in Weimar, in Nürnberg, and later yet other copies in Italy, until at present no less than twelve copies are known.
These gores were constructed to cover a sphere 41 cm. in diameter, and the map represents the entire world, with its seas, its continents, and its islands. The names of the various regions of the earth, of the several empires, and of the oceans are inscribed in Roman capital letters; the names of the kingdoms, of the provinces, of the rivers, are inscribed in cursive Italic letters, while for the names of the several peoples he employed a different form of letter. The gores, twelve in number, were engraved and printed in groups of threes (Fig. [61]), each gore having an equatorial diameter of thirty degrees. Mercator worked out mathematically the problem dealing with the proper relation of the length of each of the gores to its width, or of its longer diameter to its shorter, in his endeavor to devise a map as nearly perfect as possible in shape for covering a ball, knowing full well the difficulty of fitting a flat surface to one that is curved. Each of the gores he truncated twenty degrees from the poles, and for the polar areas he prepared a circular section drawn according to the rule applicable to an equidistant polar projection. It appears, as before noted, that he was the first to apply this method in globe construction.
Fig. 61. Six of Twelve Terrestrial Globe Gores by Gerhard Mercator, 1541.
The ecliptic, the tropics, and the polar circles are represented at their proper intervals, with other parallels at intervals of ten degrees, and meridians at intervals of fifteen degrees. As in his double cordiform map of 1538, his prime meridian passes through the island of “Forte Ventura,” one of the Fortunate Islands of the ancients, but which had long been known as the Canary Islands. To his globe map he added a feature of special value to seamen. From the numerous compass or wind roses, distributed with some regularity over its surface, he drew loxodromic lines, or curved lines cutting the meridians at equal angles.[273] This feature could not have failed to win the approval of navigators, since they well knew that the previous attempts to represent these rhumbs as straight lines on maps drawn on a cylindrical projection, led to numerous errors in navigation. A second somewhat curious and interesting feature of his globe, a feature which I do not recall to have noticed in any other, is the representation in various localities on land and on sea of certain stars, his idea being that he could thus assist the traveler to orient himself at night. In his list of stars on his globe map, we find, for example, “Sinister humerus Boötes” near latitude 40 degrees north, longitude 210 degrees; “Corona septentrionalis” near latitude 29 degrees north, longitude 227 degrees; “Cauda Cygni” near latitude 44 degrees north, longitude 305 degrees; “Humerus Pegasus” near latitude 12 degrees north, longitude 340 degrees; “Crus Pegasi” near latitude 26 degrees north, longitude 339 degrees; six of the important stars in “Ursa Major,” including “Stella Polaris,” and in the present California, somewhat strangely prophetic, “Caput Draconis.”
On the ninth gore, counting from the prime meridian eastward, is a legend giving the author’s name, the date of issue, and a reference to the publication privilege, reading “Edebat Gerardus Mercator Rupelmundanus cum privilegio Ces Maiestatis ad an sex Lovanii an 1541.” “Published by Gerard Mercator of Rupelmunde under the patent of His Imperial Majesty for six years at Louvain in the year 1541.” In a corresponding position on the seventh gore is the dedication “Illustris: Dnō Nicolao Perrenoto Domino à Granvella Sac. Caesaree Mati à consiliis primo dedecatũ.” “Dedicated to the very distinguished Seigneur Nicholás Perrenot, Seigneur de Granvella; first counselor of His Imperial Majesty,” over which is the coat of arms of the Prime Minister. On gore six we read “Ubi & quibus argumentis Lector ab aliorum descriverimus editione libellus noster indicabit.” “Reader, where and in what subjects we have copied from the publications of other men will be pointed out in our booklet,” in which there appears to be a reference to an intended publication wherein his globe was to be described and its uses indicated. No such work by Mercator is known to exist, although we find that in the year 1552 he issued a small pamphlet bearing the title ‘Declaratio insigniorum utilitatum quae sunt in globo terrestri, caelesti et anulo astronomico. Ad invictissimum Romanum Imperatorus Carolum Quintum.’ ‘A presentation of the particular advantages of the terrestrial, celestial, and armillary spheres. Dedicated to the invincible Roman Emperor Charles Fifth.’[274]