=A.D. 1632.=--Gassendi (Pierre), an eminent French savant, professor at the Royal College of France, “ranked by Barrow among the most eminent mathematicians of the age, and mentioned with Galileo, Gilbert and Descartes,” discovers that a part of the iron cross of the Church of St. Jean at Aix possesses all the properties of a loadstone after being struck by lightning and lying in one position a certain length of time. Gilbert mentions, “De Magnete,” 1600, Book III. chap. xii.) that the fact of magnetism being imparted to an iron bar by the earth was first ascertained by examining the rod upon the tower of the church of St. Augustine at Arimini (Sir Thomas Browne, “Pseud. Epidemica,” London, 1650, p. 48; U. Aldrovandi, “Musæum Metallicum,” Milan, 1648, p. 134). In the “Vie de Pierre Gassendi,” par le Père Bougerel de l’Oratoire, Paris, 1737, p. 14, it is related that during the month of September 1621, while promenading about three leagues’ distance from Aix in a village named Peynier, he observed a light in the heavens to which he gave the name of _aurora borealis_, as much on account of its location as by reason of its resemblance to the light which precedes the rising of the sun. From the “History of the Royal Society,” by C. R. Weld, 1848, Vol. II. p. 430, is taken the following, communicated by Humboldt: “The movement of the magnetic lines, the first recognition of which is usually ascribed to Gassendi, was not even yet conjectured by William Gilbert; but, at an early period, Acosta, ‘from the information of Portuguese navigators,’ assumed four lines of no declination upon the surface of the globe.... In the remarkable map of America appended to the Roman edition of the Geography of Ptolemy in 1508, we find, to the north of Gruentland (Greenland), a part of Asia represented and the magnetic pole marked as an insular mountain. Martin Cortez, in the ‘Breve Compendio de la Sphera’ (1545), and Livio Sanuto, in the ‘Geographia di Tolomeo’ (1588), place it more to the south. Sanuto entertained a prejudice, which, strange to say, has existed in later times, that a man who should be so fortunate as to reach the magnetic pole (_Il calamitico_) would then experience _alcun miracoloso stupendo effecto_” (“Cosmos,” translated under the superintendence of Col. Sabine, Vol. II. p. 280). In a footnote to the Otté translation of Humboldt, 1859, Vol. V. p. 58, it is stated that _calamitico_ was the name given to the instruments in consequence of the first needles for the compass having been made in the shape of a frog.