TO THE READER.

An ornamental woodcut initial 'N' features scrolling foliage and floral patterns within a square frame.

It does not escape me, friendly Reader, that the publication of this my dissertation on the theories of the Medicean stars original: "Medicearum." These are the four largest moons of Jupiter, which Galileo named in honor of the Medici family. deduced from physical causes will provide you an opportunity to suspect one of two things. You might think that I have been deterred by the greatest difficulties and have interrupted the laborious work on the motion of animals De Motu Animalium: Borelli's foundational work on biomechanics, which applied the laws of physics to the movement of living creatures. which I have long contemplated, and for which I gave hope of a near publication; or, that I have abandoned it entirely. Since, therefore, you see that I have by no means fulfilled my promises, I thought it worthwhile to give an account of my purpose in a few words.

Know then that in the summer of this year, a huge telescope of wonderful perfection, made by the industrious and most skillful Giuseppe Campani Giuseppe Campani (1635–1715) was a renowned Italian lens maker and astronomer whose instruments were used by the most prominent scientists of the era., was sent to the Most Serene Grand Duke of Tuscany. With this admirable instrument, we began first to observe Saturn, and then Jupiter. Then, by the command of his Highness, I derived the ephemerides Ephemerides: Tables listing the predicted future positions of celestial bodies. of the Medicean stars through calculations based on the tables of Galileo, so that their pre-determined positions might be observed daily during the evening hours with the aforementioned telescope.

Meanwhile, many things were discussed concerning the motions and positions of the Medicean stars. Thus it happened that, without noticing and even while reluctant, I became involved in such speculations. Gradually, as often happens, one speculation drawing another connected one after it, it came about that this little work slipped from my hands. When I had shown it to the Most Serene and Wise Prince Leopold Prince Leopoldo de' Medici (1617–1675) was the brother of the Grand Duke and a major patron of the sciences. He helped found the Accademia del Cimento, one of the earliest scientific societies., and submitted it to his sharp judgment...