Theories of the Medicean Planets Deduced from Physical Causes

of the eccentric orbit, the plane is inclined toward the Ecliptic Ecliptic: the apparent path of the Sun across the sky in such a way that it intersects it in a straight line B T D. The part B A D stretches toward the North original: "Boream" and is raised above the underlying plane. Conversely, the part B P D turns toward the South original: "Austrum" and is depressed below that same underlying plane. Therefore, the straight line A P, which passes through the two centers of the Earth and the Moon's orbit C, is called the line of apsides. Point A of the eccentric is called the Apogee Apogee: the point in the Moon's orbit furthest from Earth, and P is the Perigee Perigee: the point in the Moon's orbit closest to Earth. Points B and D, the common intersections of the eccentric and the Ecliptic, are called the Nodes. D is the ascending node toward the Arctic Pole, and B is the descending node toward the Antarctic. Finally, points A and P are called the Limits, specifically the positions where the latitude is greatest, which for the Moon does not exceed five degrees.

To discuss the motions, it must be understood that they can be divided into two parts. Some are the Moon's own motions in its eccentric orbit, while others depend on the solar motion. Regarding the proper motions, we must first consider the motion completed in respect to the position of the universe itself. This is the Moon's passage from point A under a specific fixed star (for example, under the beginning of Cancer) following the order of the signs from West to East, until it completes a full circle A B P D A and returns to the same point from which it departed (that is, to the beginning of Cancer). This motion of the Moon is called the motion of restoration original: "motus restitutionis," known today as the sidereal month. It is completed in 27 days, 7 hours, 43 minutes, and 5 seconds. However, since the Apogee A does not remain immobile under the same point of the zodiac but advances successively with a slow motion—so that in one day it completes nothing more than 6 minutes of a degree—it follows that after a full restoration of the Moon under the same point of the zodiac, the Moon has not yet returned to the Apogee of the eccentric from which it departed. Meanwhile, the Apogee itself has progressed from A to I by three degrees. Therefore, the Moon cannot reach that point for nearly another five full hours. This revolution of the Moon is called the cycle of anomaly original: "cursus anomaliae," known today as the anomalistic month, or inequality. It is completed in 27 days, 13 hours, 18 minutes, and 35 seconds. It is called by such a name because its motion appears slowest at the Apogee A and fastest at the Perigee P, as well as in the intermediate places B and

Vocabulary from original: Ecliptic, North, South, Apogee, Perigee, Nodes, motion of restoration, cycle of anomaly, of the Moon