Claudius Ptolemaeus; Giovanni Antonio Magini — Geographiae universae tum veteris, tum novae (1597)

and is that which is comprised within the parallel circle to the Equator, which touches the horizon and contains the hidden pole of the world. Therefore, it is proved by the same Ptolemy in the second chapter of the first book of the Almagest Great Composition, not only the motion of the heaven from East to West from the motion of the fixed stars, but also its round form. Regarding the earth, however, Ptolemy says that it is not possible to have any certainty about it, because it is not possible to see it all at once nor for the greater part while remaining in only one place, as is done with the heaven, since it does not surround us as the heaven does: nor is it any less possible for the whole earth to be traveled around by the same men on every side so that its length and width could be investigated. It is, however, quite true that its roundness and magnitude can be known from the appearances which happen in the heavens, just as Ptolemy does in the third chapter of the first book of the Almagest, where he demonstrates the earth to be of a spherical figure, and in the fourth, he concludes it is situated in the middle of the universe; in the fifth, moreover, he shows the earth to be like a point compared to the immensity of the heaven. Likewise also, in the sixth chapter, he joined that the earth rests in the middle of the universe. Finally, so that I might impose an end to this chapter, I will not fail to say that Ptolemy did not say without reason that the knowledge of the vertical fixed stars, and of those which rise and set in every place, is most high and beautiful, because it is very curious and necessary for observing and knowing changes in the air, and calamities which occur in any place, such as rains, hail, snow, winds, thunder, inundations of waters, the harvest, famine, pestilence, earthquakes, mortality of peoples, and similar things, all of which depend, as they seem, on various meetings of the planets among themselves and with the fixed stars, and on the diversity of the risings and settings of the fixed stars. How much vertical stars count can be known from the tenth chapter of the Supplementum Almanach Supplement to the Almanac by Cardano, and from the fourth chapter of the Tabulae Bergenses Bergen Tables of Johannes Stadius; for those which once a day become perpendicular to that city or place have great power and familiarity in that place, as for example the head of the Gorgon, or Medusa, which is a star placed in the 21st degree of Taurus with 23 degrees of North latitude, becomes vertical at this time to Toledo and Naples. When, therefore, Saturn—which is a planet cold by its own nature—transits through the middle of the heaven together with the said star in the year 1559, it caused there in those places a cold and most harsh winter, as Stadius narrates, although elsewhere it was quite mild and pleasant.

On the second chapter.

Therefore let this be the end of him who wishes to practice Geography, etc. Here Ptolemy wishes Geography to have its own principles and foundations from which it arises and is built, without which it could in no way exist, among which the most important is the history of journeys which have been made by one or more men skilled in speculative science, who have observed many terrestrial and maritime places, omitting nothing which could contribute to this description of the world. The same author later adds that this history of the knowledge of places can be completed in two ways by those who have traveled the world, either Geometrically or Astronomically. Geometric knowledge depends on the dimension of the distances which places have from one another, by observing furthermore the position of places and their site. Which geometric measure is

material or manual, that is, determined and exactly quantified by poles, or ropes, or paces: or also the measure of time, as it would be if one considered the journey which a pedestrian can complete in so many hours, or a horse, since the journey itself has first been explored for the space of an hour, or half an hour, succeeding afterwards the said journey with an equal pole or rope. Or also by considering the journey which a ship can complete in such time, having taken into account, however, the speed of the ship, the force of the winds, and the motion of the water. As for the position or site of places, one must understand that wind, or that part of the world, toward which one place is inclined with respect to another; and one must imagine the first place, to which the comparison of the others is made, to be like the center of a circle, on the circumference of which are marked the principal parts, or regions of the world, namely East, West, North, and South; or the principal winds, which are twelve according to the ancients, as appears in this Table.

A diagram depicts an armillary sphere or globe surrounded by twelve personified wind heads. The top winds include Trascias/Circius, Aparctias/Septentrio, and Boreas/Aquilo. The right side features Cecias/Hellespontius, Apeliotes/Subsolanus, and Eurus/Vulturnus. The bottom includes Euronotus/Vulturno-Auster, Auster/Notos, and Libonotus/Austro-Aphicus. The left side includes Aphicus/Lips, Favonius/Zephyrus, and Argestes/Corus.

Whence, departing from that first place and proceeding to another, it will be necessary for that distant place to be found either precisely in a straight line of one of these regions of the world, or of one of the principal winds; or it will recede a little from it by such and such degrees, such as ten, twelve