There is to be found in the Mathematical Salon of Dresden a fine example of the work of Christian Heyden (1525-1576), son of a rector of the St. Sebaldus School of Nürnberg. Doppelmayr[310] tells us that after years of study in Leipzig and Wittenberg, he returned to his native city, became interested in making mathematical instruments, and in 1564 he was appointed to a professorship of mathematics in the famous Nürnberg gymnasium. His biographer does not refer to his activity as a globe maker, but tells us that about the year 1570 he constructed for the Emperor Maximilian II a mechanical device for illustrating the movement of the sun and the moon, which instrument, he notes, especially interested the noted Frenchman, Petrus Ramus, who carefully examined it on the occasion of a visit to Nürnberg. The Dresden example of his work (Fig. [67]), the only example known, consists of a brass celestial globe encased in a covering of brass, on the surface of which is engraved a terrestrial map. It has a diameter of 72 cm., the whole being furnished with a horizon, a meridian, and an hour circle. This is indeed a choice specimen of a sixteenth-century engraved metal globe, of which we have numerous examples, but it is rather an ornamental piece than one of great scientific value.
Fig. 67. Globe of Christian Heyden, 1560.
Doppelmayr likewise gives us a brief biographical note referring to one Johannes Praetorius, a globe maker, born at Joachimsthal in the year 1537.[311] After a considerable period of study, chiefly at Wittenberg, where he turned his attention to the philosophical and mathematical sciences, he took up a residence in Nürnberg in the year 1562. Here he became interested in the construction of mechanical and astronomical instruments, and soon won the favor of the Emperor Maximilian II, which favor he enjoyed to the end of that Emperor’s reign. It was about the year 1576 that he became a professor of mathematics at Altdorf, where he died in the year 1616. Doppelmayr refers to a number of the mathematical and astronomical instruments constructed by him, noting that in the year 1566 he completed two globes of metal richly gilded, each having a diameter of 11¼ inches, that each was furnished with an hour circle, a movable quadrant and semicircles, and that a compass was set in the base of each. We learn also from the same biographer that in the year 1568 he completed a brass astrolabe having a diameter of “one schuh” (foot?), three and one half inches, and that it was supplied with all parts essential to a complete apparatus of its character. We are further informed that shortly after the beginning of his career in Altdorf he undertook the construction of a large celestial globe of wood and paper, having a diameter of four Nürnberg feet, that he was assisted in this work by the artist and draughtsman, Christopher Heinrichs, and that on the surface of the sphere one thousand six hundred and fifty stars were indicated with appropriate accompanying inscriptions.
Two pairs of Praetorius’ globes are now known, one pair in the Mathematical Salon of Dresden (Fig. [68]),[312] and the other in the Germanisches National Museum of Nürnberg. These globes are of brass, each having a diameter of 28 cm.; each is supplied with meridian, horizon, and hour circles and rests on a tripod base. They are richly engraved pieces, the terrestrial example being remarkably well preserved, the celestial being slightly injured, through rubbing which has removed parts of certain figures of the constellations.
Fig. 68. Globe of Johannes Praetorius, 1566.
Among those Italians who, in the sixteenth century, acquired well-merited fame as globe makers may be mentioned Ignazio Danti (1536-1586),[313] known as Pellegrino before he entered the order of the preaching friars in his nineteenth year. The name Danti appears to have been given him chiefly on account of his great learning, particularly in the field of mathematics and astronomy. In the same branches of science his father had achieved distinction, and likewise his grandfather, Vicenzo de Rinaldi, who, in the year 1571, issued a translation of the ‘Sfera’ of Sacrobosco, and who constructed, as we are told, an astrolabe and an armillary sphere.[314] It seems to have been early in the year 1563 that Danti was called to Florence by Duke Cosimo for the purpose of constructing, under his patronage, nautical and astronomical instruments and geographical maps. Of his work which is still known to us there may be first mentioned an astronomical quadrant placed on the façade of the church of Santa Maria Novella, and an equinoctial armilla placed within the same church. We have first mention in Vasari’s ‘Lives’ of the globe and map work of his which especially concerns us here. It is an interesting account of his activity in this field, an account worthy of citation. “Fra Ignazio Danti is very learned in cosmography and a man of distinguished ability in letters, in so much that the Duke Cosimo has committed to his care a work than which none more perfect in design, or more important in the results to be expected from it, has ever been executed in that kind. His excellency has caused a room of considerable extent to be prepared on the second floor of his palace, as a continuation of, and an addition to the guardaroba; around this room he has had cabinets arranged seven braccia high, and richly carved in walnut wood, intending to place within them the most valuable and beautiful works of art in his possession; and on the doors of the same he has caused fifty-seven pictures, about two braccia in height and of proportionate width, to be painted in oil on wood in the manner of miniatures. The subjects delineated are the Ptolemaic Tables, measured by Don Ignazio with the most exact perfection, and corrected according to the latest authorities; sea-charts of the utmost accuracy are added, the scale and the degrees being adjusted with all possible care, and all having the ancient, as well as the modern, names; the division made of these works being as follows. At the principal entrance into the room are seen four pictures executed on the sides of the cabinets, and representing in perspective the halves of four spheres, those below showing the earth, and those above the heavens with all their signs and celestial figures. Proceeding toward the right we have all Europe depicted in fourteen compartments, the pictures succeeding each other to the center of the wall which is at the head of the room, and opposite to the principal door, that namely whereon is placed the horologue with its wheels, and the daily motions made by the planets in their spheres; I mean that so much renowned clock made by the Florentine Lorenzo della Volpaja. Above the compartments representing Europe, are those of Africa in eleven divisions; these extend to the horologue itself, beyond which and on the lower part is Asia, which occupies a consecutive range of four compartments, extending to the principal door. There are besides the West Indies, which commence from the clock, and continue to the principal door; the whole series forming the fifty-seven divisions before mentioned. On the lower part of the walls and immediately beneath the geographical delineations, in an equal number of compartments will be the various plants and animals produced by the respective countries, all depicted from nature. Over the cornice of the said cabinets, which completes the decorations, there are to be niches dividing the pictures, and in these will be placed certain antique busts in marble, representing the Emperors and Princes by whom these lands have been possessed, so far as those portraits are known to exist or can be procured. The ceiling is entirely in carved wood-work, and within the compartments of the same are twelve large pictures, in each of which are to be four celestial signs, making in the whole forty-eight; the figures are to be but little less than life size, each accompanied by its stars. On the walls beneath are three hundred portraits of distinguished persons belonging to the last five centuries, or somewhat more; they are painted in oil; but, that I may not make too long a story, I refer the mention of their names to the tables of my work. All have frames of similar size, very richly carved in oak, and producing an exceedingly fine effect.”