How great was the direct influence of Mercator on globe making activities, it may not be easy to trace, but the evidence seems to be conclusive, as Breusing has noted, that his should be counted the greatest, among those active within this field, for fifty years and more, following the issue of his first work in the year 1541. It is among the Italian globe makers, and those in the peninsula interested in such instruments, that we seem to find the first and most striking evidence of his influence, which will be noted in the following pages.
Giovanni Gianelli of Cremona is referred to, by certain early Italian writers, as a clock and globe maker of remarkable ability,[284] the justice of which estimate is abundantly supported by the character of the one example of his handiwork extant, belonging to the Biblioteca Ambrosiana of Milan, to which it came from the collection of Canon Manfred Settàla about the middle of the seventeenth century. This is an armillary sphere of brass, the diameter of its largest or zodiacal circle being 14 cm. This circle is graduated and has engraved on its outer surface the names of the twelve constellations. It is likewise provided with a graduated equatorial circle, with polar circles and those representing the tropics. At the common center of the several rings is a small ball, 5 cm. in diameter, which is made to serve as a terrestrial globe. On one of the circles is the inscription “Janellus MDXLIX Mediolani fecit,” and we further find inscribed the name “Hermetis Delphini,” which perhaps tells us of a one-time possessor. In a volume describing the museum of Canon Settàla, and issued in the year 1666, Gianelli and his work are thus referred to:
“To that great man Gianelli of Cremona there is due great honor, whose personal qualities made him an especial favorite of His Catholic Majesty Philip II. Among the many globes which he constructed our museum possesses one of surpassing excellence, in that it exhibits, in addition to other movements, that which astrologers call the movement of trepidation, and which movement was set forth in theory by Thebit.”[285]
The Emperor Charles V, when in Pavia, we are told, had his attention directed to an armillary sphere constructed by Dondi in the fourteenth century. On finding this sphere much injured by rust and usage he called upon Giovanni Gianelli to restore it, but it was reported to be beyond repair. Thereupon the Emperor gave direction to have the sphere reproduced, which, when completed, was carried by His Majesty to Spain. No trace of this work by Gianelli can now be found.
Girolamo Fracastoro, a distinguished Italian physician, a famous man of letters, and a great philosopher of the first half of the sixteenth century, was also a skilful globe maker, as we learn from Ramusio,[286] and from the sketch of his life which usually appears as an introduction to his collected works.[287]
Vasari also gives us certain information concerning him, noting that he assisted Francesco dai Libri in the construction of his large globe,[288] and we are led to believe that he was often consulted as an expert by globe makers of his day. While none of those he may have constructed are extant, what is known of his interest in these aids to geographical and astronomical studies entitles him here to a word of reference.
Ramusio says[289] that on the occasion of a visit, with the architect Michele S. Micheli, to the home of their common friend, Girolamo Fracastoro, at Caffi, they found him in the company of a gentleman, a very distinguished philosopher and mathematician, who was showing him an instrument based on a newly found movement of the heavens; that after they had considered for some time this new movement, they had brought before them a large and very detailed globe of the entire world, and about this the distinguished gentleman began to speak. Fiorini argues, somewhat ingeniously, that this globe may have been one constructed by Mercator in 1541, if not one by Libri, in the making of which Fracastoro himself had assisted. The letters of Fracastoro assure us that he made use of globes in his geographical and astronomical studies, and that his friends did likewise. January 25, 1533, he wrote Ramusio, “If you should chance to speak to that master who made your metal spheres, I should like you to ascertain how much a simple but perfect one, one foot in diameter, would cost.” Writing again to Ramusio January 10, 1534, concerning the “Southern Cross,” he adds: “Just reflect a little, and if you have not sent away the celestial globe, look at that Centaurus and you will find all that I am writing to you. You might perhaps write about these doubts to Mr. Oviedo, or perhaps I might; it would be a good idea and we might ask him about the very prominent star in the right foot to ascertain whether it is a separate star or is one of those in the ‘Southern Cross.’” On the twenty-fifth of January, 1548, he again wrote to Ramusio: “On my globe Zeilan is just below the Cape of Calicut, on the equinoctial line, and it may be that which Jambolo discovered was Zeilan or Taprobana; I am inclined to believe it was Taprobana.” His letter of May 10, 1549, also to Ramusio, is of special interest, indicating, as it does, his estimate of the value of terrestrial and celestial globes in the study of astrology (astronomy) and geography. “In regard to what you write me about M. Paolo, I thoroughly approve of his taking up the sacred study of astrology and geography, subjects of study for every learned gentleman and nobleman, as he would have as his guide and teacher the very well-known Piedmontese to whom we owe so many excellent things, but first I should advise you to have M. Paolo construct two solid spheres. On one of these should be represented all the celestial constellations, and the circles should all have their place, that is to say, not as Ptolemy represents the stars as they were located in his time, but according to the investigations of our own times, that is, about twenty degrees further east. The other should be a terrestrial globe constructed according to modern ideas, which he should always follow in his studies. He will use the first globe for a thousand and one things; it will be his guide by day and by night, and by making use of the quadrant he will be able easily to locate the things to be seen in the heavens. Then when he shall have been well started I want that you should have him read that little book of mine on homocentricity, wherein he will be able to learn what astrology is, but for the present let him learn ordinary astrology which has been treated in so barbarous a manner as to lose much of its dignity.” Writing again from Verona January 21, 1550, to Paolo, after telling him what he should point out to his father, he says: “You will tell him also that M. Michele di San Michele has seen my globe and that he likes it.... When I come I will make note of the principal places, for I desire very much to verify them with the report of navigators telling what they have found, concerning which matter, I think, no one knows more than you do, or especially your distinguished father. As to the celestial sphere, I should like very much to compare one I have with the one your father is having made, that I may learn how the constellations compare, and how many more of the fixed stars have been inserted. I have changed their position twenty degrees. Whether he agrees with me or not I do not know.”
NOTES
[198] Harrisse. Discovery, p. 247.
[199] This is clearly recorded in such important maps as the Cantino, Canerio, Waldseemüller, Schōner globe maps of 1515 and 1520, Boulengier gores, Liechtenstein gores, et al.