Philolaus, the Pythagorean, was born at Crotona and flourished about 374 B.C. He was a disciple of Archytas, was the first known writer on the subject of physics, and it is said his writings were so highly esteemed that Plato employed three books of Philolaus for the composition of his “Timæus.” Gilbert says (De Magnete, Book VI. chap. iii.) that Philolaus, whom he calls an illustrious mathematician and a very experienced investigator of nature, would have the earth to be one of the stars and to turn in an oblique circle around the fire, just as the sun and moon have their paths.
In the “Abhandlungen zur Geschichte der Mathematik,” Leipzig, 1899, Vol. IX. pp. 275–292, will be found “Note sur le charactère de l’astronomie Ancienne,” by Paul Mansion, explaining the seven systems of Ancient Astronomy and showing the centre of the world to be, according to Philolaus, a central fire, or vital flame of the entire planetary system; whilst Eudoxus,[66] Ptolemæus and Tycho Brahé believed it to be the earth immovable; Heraclides of Pontus asserted that it was the earth rotating from West to East; and both Aristarchus and Copernicus maintained that it was the Sun.
References.—Fabricius (Johann Albert), “Bibliotheca Græca”; Rose’s “New Gen. Biog. Dict.,” London, 1850, Vol. XI. p. 102; Houzeau et Lancaster, “Bibl. Gén.,” Vol. II. p. 224; Chaignet (Antelme Edouard), “Pythagore et la Philosophie Pythagoricienne,” 1873; Humboldt, “Cosmos,” 1859, Vol. I. p. 65; Larousse, “Dict. Univ.,” Vol. XII. p. 823.
Philostratus, Flavius, to whom Gilbert alludes briefly at Chap. XXXVIII. book ii. of his De Magnete as affirming that the stone pantarbes attracts to itself other stones, was an eminent Greek sophist, born at Lemnos between 170 and 180 A.D., whose only writings known to us are accounts of the lives of Apollonius of Tyana[67] and of the Sophists. These were first published, Paris, 1608, and a part thereof have found a good translator in M. A. Chassang, who entitled his book “Le Merveilleux dans l’Antiquité,” Paris, 1862.
References.—Letronne (Jean Antoine), “Mém. de l’Acad. des Inscrip.,” N. S., Vol. X. p. 296; Gibbon (Edward), “Roman Empire,” Vol. III. p. 241; Ritter (Dr. Heinrich), “Hist. de la Philos. Ancienne,” Vol. XII. chap. vii.; Fabricius (Johann Albert), “Bibliotheca Græca,” Vol. V. p. 540; Miller, in the “Journal des Savants,” 1849; “Biog. Gén.,” Vol. XL. pp. 3–5; ninth “Encycl. Britan.,” Vol. XVIII. pp. 796–797.
Plancius, Peter, who is alluded to in Edward Wright’s address to Gilbert, was a Dutch theologian and astronomer—“a most diligent student, not so much of geography as of magnetic observations”—(1552–1622), the first to recommend the Dutch expeditions to the Indies and who prepared the necessary instructions and maps to ensure their success. His universal map has been alluded to at the Blundeville entry, A.D. 1602. In the article on Dr. Kohl’s Collection of Early Maps (“Harv. Univ. Bull.,” Vol. III. p. 305) allusion is made to a map of America by Peter Plancius, 1594, which is spoken of by Blundeville in his “Exercises” as “lately put forth in the yeere of our Lord 1592.”
References.—Wagenaar (Jan), “Histoire de la Hollande,” Vol. IX. p. 140, and also “Histoire d’Amsterdam,” Vol. I. p. 407, and Vol. III. p. 219; “Biog. Gén.,” Vol. XL. p. 403; Larousse, “Dict. Univ.,” Vol. XII. p. 1129.
Plotinus of Alexandria, the father of Neoplatonism, lived 205–270 A.D. His writings were left to the editorial care of Porphyry, who arranged them in six divisions, each of which was subdivided into nine books, or Enneads. Plotinus maintains that men belong to two worlds, that of the senses and that of pure intelligence, and it depends upon ourselves as to which one we will direct most our thoughts and finally belong. The fire-firmament of Plotinus is alone referred to by Gilbert in the third chapter of the last book of De Magnete.
References.—“Neoplatonism,” and works cited in the Encyclopædias, also the works on Plotinus, especially by Kirchner (Carl), 1854, by Brenning (Emil), “Die Lehre ... Plotin ...” (1864), and by Kleist (E. C. von) (1884); Plotini, “Operum Philosophicorum Omnium,” Basilæ, 1580, Liber III, Ennead II, p. 115; Kingsley (Charles), “Alexandria and her Schools,” Camb., 1854; Grucker (Emile), “De Plotinianis,” Paris, 1866; Lewes (George Henry), “History of Philosophy from Thales to Comte,”[68] London, 1867; Larousse, “Dict. Univ.,” Vol. XII. p. 1198; “Biog. Gén.,” Vol. XL. pp. 487–494; Dr. Fried. Ueberweg, “Hist. of Philos.,” tr. of Geo. S. Morris, 1885, Vol. I. pp. 240–252; Bouillet (Marie Nicolas), “Les Ennéades de Plotin,” 1857.
Ptolemæus, Claudius, the great Egyptian mathematician, geographer and astronomer who flourished in middle of the second century after Christ, is frequently alluded to throughout four of the books of De Magnete, and Gilbert makes direct reference to the “Opus Quadripartitum,” “Cosmographia” and “Geographia.” The last is, however, the work with which Ptolemy’s name is most prominently connected. It was the standard up to the time of the marine discoveries of the fifteenth century, and has been translated and published into editions too numerous to mention here.