He tells us in one of his legends how to find the distance between two places represented on the globe, observing, “Si quorum voles locorū distantiā cognoscere ... trāsferto, hic tibi, q̄ libet particula ĭtercepta millaria referet, Hisp: 18, Gal: 20, Germ: 15, Milia pass; 60, Stadia 500,” from which it appears that he gives as the value of an equatorial degree 60 Italian miles or 500 stadia, equivalent to 18 Spanish miles, to 20 French miles, and to 15 German miles. Finding numerous errors in Ptolemy’s geography of the Old World, he tells us that he undertook to correct these errors from the accounts of Marco Polo, whom he calls “M. Paulo Veneto,” and from the accounts of Vartema, whom he calls “Ludovico, Rom Patricii.” Between parallels 50 degrees and 60 degrees south latitude and meridians 60 degrees and 70 degrees east longitude is the inscription “Psitacorum regio a Lusitanis anno 1500 ad millia passum bis mille praetervectis, sic appellata quod psitacos elat inaudite magnitudinis, ut qui ternos cubitos aequent longitudine.” “Region of parrots discovered by the Portuguese in 1500 who sailed along 2000 miles; so called because it has parrots of unheard-of size, measuring three cubits in length.” America, he notes, is called New India, “America a multis hodie Noua India dicta.” In the Antarctic region an inscription tells of the notion entertained by many geographers of his day and by some in an earlier day, that in addition to the four known parts of the world, Europe, Asia, Africa, and America, there is here a fifth part of large size stretching for a number of degrees from the pole, which region is called “terra Australe.” Mercator undertook, in Chapter X of his ‘Atlas,’ to demonstrate that a large Antarctic continent must of necessity exist as a balance to the weight of the other four continents or parts of the world lying in the northern hemisphere.[275]
In 1551 he issued his copper engraved gores for a celestial globe, dedicating the same to Prince George of Austria, natural son of the Emperor Maximilian, who was Bishop of Brixen, Archbishop of Valencia, and Bishop of Liège in the year 1544. A set of these gores was likewise acquired by the Royal Library of Brussels at the same time it acquired the terrestrial globe gores referred to above.[276] The dedication reads “Ampliss: Preculi Principiqȝ Illmo Georgio ab Austria Dei dispositione Episcopo Leodiensi, Duci Bullonensi, Marchioni Francimotensi, Comiti Lossensi &c̃ mecaenati optime merito dd. Gerardus Mercator Rupelmundanus.” “To the Magnificent Protector and Prince, the very distinguished George of Austria, by the Grace of God, Bishop of Liège, Duke of Bouillon, Marquis of Francimontensi, Count of Lossensi, the very splendid patron of arts and science, dedicated by Gerard Mercator of Rupelmunde.” Near the above inscription we find the date and place of issue given as follows, “Lovanii anno Domini 1551 mense Aprili,” and a reference to his privilege “Inhibitum est ne quis hoc opus imitetur, aut alibi factum vendat, intra fines Imperii, vel provinciarum inferiorum Caes: Mt̄is an: te decennium, sub poenis & mulctis in diplomatibus cotentis. Oberburger & Soete subscrib.” “All persons are forbidden to reproduce this work or to sell it when made elsewhere within the Empire or the Low Countries of His Imperial Majesty until after ten years, under the penalties and fines prescribed in the patent. Signed by Oberburger and Soete.” It clearly was the intention that this should serve as the companion of his terrestrial globe of 1541, described above, since the gores are of the same size, each of the twelve being truncated in the same manner, and the circular section being prepared for the polar areas. Mercator’s merits as an astronomer by no means equaled his merits as a geographer. However, his celestial globe, by reason of the exactness of the composition, by reason of its simplicity, and by reason of the artistic skill exhibited in the workmanship, is a most worthy work of that great scientist. On this globe are represented the forty-eight constellations of Ptolemy, to which have been added three which he calls Antinous, Lepus and Cincinnus, the first formed of six stars and located on the equator below the constellation Aquila, the second in the southern hemisphere under the feet of Orion, and the third in the northern hemisphere near the tail of Ursa Major.[277] His constellations, as well as the principal stars in the same, have, in the majority of instances, Greek, Latin, and Arabic names. It does not appear that Mercator felt himself bound to a strictly scientific representation and interpretation of the celestial bodies, for he pays more or less homage to astrology, inscribing on the horizon circle of his globe the horoscope as used by astrologists in calculating nativities, perhaps recognizing, from a business standpoint, the advantage of an appeal to certain superstitions which he found still lingering among both the learned and the unlearned.
By reason of their size and the great care with which they had been prepared, his globes must have found general favor, not only with those of rank and distinction, for whom copies de luxe were issued, but with geographers and scholars in general, who found it possible to obtain at a comparatively small price the more modest copies. That they found favor in Germany is assured us by Mercator’s correspondence with Camerarius of Nürnberg, in which mention is made of the sale of six pairs of his globes in that city, and of others at the Frankfort book market.[278] Thomas Blundeville tells us in his ‘Exercises’ that Mercator’s globes were in common use in England until 1592,[279] and the number of his globes which have become known since 1868 in various parts of Europe assure us that copies of that master’s work must have been easily obtainable by those interested. Ruscelli, in referring to printed spheres; notes that they usually were made small, and that those of large size are not exact, but he adds that he had seen some that were three and one half palms in diameter, such as that which years ago Aurelio Porcelaga sent to him to examine, printed in Germany, and given to him by Monseigneur Granvella, to whom or to whose father, not recalling which, it had been dedicated, but which he remembered was very beautiful and very exact, being evidently engraved by one very expert, judged by the beauty of the design and the artistic quality of the letters.[280] Fiorini is of the opinion that these globes were Mercator’s, and that they were carried into Italy in the late years of the sixteenth century when a friendly relationship existed between certain Italian princes and the Spanish authorities then ruling in Flanders.[281]
Attention has been called above to the acquisition by the Royal Library of Brussels of a copy each of the terrestrial and the celestial globe gores, and that the discovery of the same having created an especial interest in his work, other examples were soon brought to light in Italy, in Spain, in France, in Germany, and in Austria. A pair may be found in the Muséum Astronomique of Paris, a pair in the Royal Library of Vienna, a pair in the Germanisches National Museum in Nürnberg, a pair in the archives of the town of St. Nicholas de Waes, a copy of the terrestrial globe in the Grand Ducal Library of Weimar, a copy of the celestial in the Convent of Adamont, Istria, and a copy of the terrestrial in the Convent of Stams, Tyrol. Dr. Buonanno, director of the Biblioteca Governativa of Cremona, in 1890 briefly described a pair of Mercator’s globes belonging to that library, and what he was able to learn as a result of their damaged condition of Mercator’s method of construction is not without interest. He found that over a framework composed of thin, narrow strips of wood had been pasted first a cloth covering, over this a thin layer of plaster and that to this was added a covering of a pastelike substance about six or seven millimeters in thickness, consisting of plaster, wood fiber, or sawdust, and glue. On this prepared surface had then been pasted the engraved gores. The learned librarian’s conjecture as to the manner in which these globes found their way into Italy, if correct, is of interest, pointing as it does to the formation of a great art collection in that period. He recalls that Caesar Speciano, Bishop of Cremona, had been sent in 1592 as nuncio to Germany, and that he had occasion, during his mission, to attend to certain matters pertaining to the inheritance of William, Duke of Cleves, in whose country there must still have existed the workshop of Mercator. The opinion is expressed that on the return of the Bishop to Italy he carried with him many books and art objects, which had come into his hands either through purchase or through gift, and that the same passed into the possession of the Cremona Library, a library belonging to the Jesuits until the time of the suppression of that order.[282]
The Biblioteca Municipale of Urbania possesses a pair of Mercator’s globes of 1541 and 1551, which are reported to be in a fair state of preservation. It is thought that they may have come into the library’s collection through the last reigning member of the house, Duke Francesco Maria.
In the Museo Astronomico of Rome two copies of the terrestrial globe of 1541 may be found, and a copy of the celestial of the year 1551. These, it will be seen from the reproduction (Fig. [62]), are not in a good state of preservation, although a very considerable portion of the map records can be read.
Fig. 62. Terrestrial Globe of Gerhard Mercator, 1541.
In addition to the globes of Mercator referred to above, it is known that after taking up his residence in Duisburg he constructed a small celestial globe of glass, on the surface of which he engraved with a diamond the several constellations, and that he likewise constructed a very small terrestrial globe of wood, apparently such as were later called pocket globes, having all geographical records given as accurately presented as on the larger globes.[283]