Gauging the Herschels’ star gauging programme

Drawing on from ancient and modern authors, Muñoz held a mix of cosmological views, resulting from his own reflexions and creativity but rooted in the most widely accepted ancient authorities of his time, Aristotle and Ptolemy. Nevertheless, as Brotons notes, his departure from the Aristotelian tradition shows many affinities with the Stoic tradition. For example, Muñoz disagreed with Aristotle on the existence of celestial spheres. According to Muñoz, all the universe was filled with air except for the space occupied by the Earth at its centre. This cosmic air had no sharp discontinuities but became progressively rarefied with the increasing distance from the Earth. It was in this medium that the planets moved like fish in the sea or the birds in the sky. In his view, the heavens are corruptible and the planets and stars are composed of elements and qualities of a terrestrial character but in a purer state. Illustrations are generally well placed and useful but unfortunately the promised photograph of an astronomical radius (pp. 102–3, note 138), in fact the only known complete radius by Gualterus Arsenius, dated 1563 and preserved in the National Museum of Science and Technology, in Madrid, appears on p. 59. Bringing together in a coherent and updated narrative the previous studies on Muñoz produced by Navarro Brotons, this book will certainly remain, for many years to come, the standard reference on this influential Spanish astronomer and humanistic scholar.