Calaber, Hannibal Rosetius. Of all the authors cited by Gilbert, this is the only one, who, thus far, cannot satisfactorily be identified, although exhaustive efforts to this end have been made by the authors of both the English translations of De Magnete. One interpretation (Hannibal, of Roseto in Calabria, shown on map at end of Vol. I. of "Briefe uber Kalabrien und Sizilien," Göttingen, 1791), has as yet found no endorsement.

"

Calcagninus, Cælius, Italian philosopher and astronomer (1479– 1541) is the author of "Quomodo Cœlum stet, terra moveatur wherein he asserts that the earth turns around the sun, also of "De Re Nautica," containing a good account of ancient ceremonies and observations, as well as of a Commentary on Aristotle, and of many creditable poetical effusions published 1533. His complete works appeared at Basle during the year 1544, and a list of them, fifty-six in all, is given by Jean Pierre Nicéron in his "Mémoires pour servir à l'histoire des hommes illustres," Paris, 1727-1745.

References.-Calcagnini (T. G.), “Della vita . C. Calcag"; Ginguené (Pierre Louis), "Histoire Litéraire d' Italie," Vols. IV, VI and VII; Paul Jove-Jovius-Giovio (b. 1483, d. 1552), "Eloges"; Borsetti, Ferranti Bolani (Ferrante Giovanni), "Historia almi Ferrariæ Gymnasii," 1735 Biog. Gén.," Vol. VIII. pp. 159-161; Larousse, 'Dict. Univ.," Vol. III. p. 109; Houzeau et Lancaster, "Bibl. Gén.,' Vol. II. p. 98; Gilbert, De Magnete, Book I. chap. i.

Cardanus, Hieronymus (1501-1576), who is so very frequently mentioned by Gilbert, throughout Books I, II, III and IV, was an Italian physicist whose writings are extremely numerous and are well reviewed in the best edition of his works published at Lyons during 1663. Those by which he is best known are the "Ars Magna," "De Rerum Varietate, Libri XVII," and the "De Subtilitate, Libri XXI," which may be considered the exponent of all his scientific knowledge and a notably good translation of which, in French, by Richard Leblanc was published in Paris, 1556.

REFERENCES.-Morley (H.), "Life of Cardan," 1854, wherein, Vol. II. pp. 56-70, will be found a long account more particularly of the contents of De Subtilitate "; Larousse, Dict. Univ.," Vol. III. pp. 376-377; Dr. Fr. Ueberweg, "Hist. of Philosophy," tr. of Geo. S. Morris, 1885, Vol. II. p. 25; Walton and Cotton, Complete Angler," New York and London, 1847, Part I. p. 142; Houzeau et Lancaster, "Bibl. Gén.," Vol. II. p. 101.

Nicolaus

Copernicus, Koppernik-Zepernic- celebrated astronomer, native of Poland (1472-1543), whose studies led him to reject the Ptolemaic system of the universe, and who proposed the one now bearing his name, is the author of "De revolutionibus orbium cœlestium," which was published May 24, 1543, a few days before his death. He is alluded to by Gilbert (De Magnete, Chaps,

II, III, VI, IX, of book vi.), who calls him "the restorer of astronomy" and and "a man most worthy of the praise of scholarship." The life and labours of Copernicus are fully detailed, in chapter treating of "Discoveries in the celestial spaces " of the "Cosmos," by Von Humboldt, who, in relation to a passage in "De Revolutionibus," makes the following very curious note: "It very singularly happens that in an otherwise instructive memoir (Czynski, Kopernik et ses travaux," 1847, p. 102)," the Electra of Sophocles is confounded with electric currents. The passage of Copernicus (quoted in Latin) is thus rendered: 'If we take the sun for the torch of the universe, for its spirit and its guide-if Trismegistes call it a God, and if Sophocles consider it to be an electrical power which animates and contemplates all that is contained in creation . . .

"Four men, Gutenberg, Columbus, Luther and Copernicus, stand at the dividing line of the Middle Ages, and serve as boundary stones marking the entrance of mankind into a higher and finer epoch of its development " (Kapp (Friedrich), Geschichte, etc., I). References.—-Westphal (E. J.), Nikolaus Kopernikus" ("Biographie des Copernicus "); Delambre (J. B. J.), "Histoire de l'astronomie Moderne"; "Journal des Savants ” for February 1864 and for December 1895; Larousse," Dict. Univ.," Vol. V. pp. 66-67; Edw. S. Holden in Pop. Sc. Monthly" for June 1904, pp. 109-131; Phil. Magazine, Vol. XIX. p. 302; Gassendi (Pierre), in Nicolai Copernici Vita," appended to his biography of Tycho ("Tychonis Brahei Vita," 1655, Haga Comitum, p. 320); W. Whewell, "Hist. of the Ind. Sciences," New York, 1858, Vol. I. pp. 257-290; the article at pp. 378–382, Engl. Cycl.,' which abounds in references; Rheticus, Narrat. prima"; Kepler (Johann), De Temporis "; Horrebow (at A.D. 1725-the_luminous process of the sun, a perpetual northern light); Houzeau et Lancaster, "Bibl. Gén.,” Vol. II. pp. 109-113, for an extended list of authorities, and also pp. 1571-1572; Joachimus (Georgius) surnamed Rhecticus, who quotes many works on Copernicus.

Cordus, Valerius-Eberwein-celebrated German botanist (1515-1544), who is alluded to by Gilbert, Book I. chap ii. wrote a Commentary on Dioscorides, published by Egénolphe in 1549, as well as an extensive history of plants, which is to be found in the Strasburg editions of his works, issued during 1562 and 1569.

References.-" Biog. Générale" (Hofer), Vol. XI. pp. 804-807; Larousse (Pierre), Grand Dictionnaire Universel," Vol. V. p. 133; "Vitæ med. Germ."; Adam (Melchior), "Lindenius renovatus "Thesaur. Lit. Botan.," 1851, PP. 52, 334; Camerarius, "Vita Melanchton"; Linden (Joannes Antonides van der), " De Scriptis Medicis," 1651, pp. 572-573; "Dict. Historique de la Médecine," par N. F. J. Eloy, Mons, 1778, pp. 705–707, Vol. I.

Cortesius, Martinus, celebrated Spanish geographer who died about 1580, is the author of the well-known and extremely scarce work, "Breve compendio de la esfera, y de la arte de navegar," Cadiz, 1546 1551, and Seville, 1556, which was translated by

Richard Eden, 1561, 1589, 1609. Of the 1556 issue, Salva remarks (II, 3763): "2e édition aussi rare que la première. C'est cet ouvrage qui a revolutionné la science nautique et qui fut le premier à indiquer la déclinaison de l'aiguille. Les instructions pour construire des mappemondes ne sont la partie la moins intéressante du texte et pourraient être utiles à tous ceux qui sont incapables de comprendre le principe des roses de vents et des loxodromes, qui couvrent la surface des cartes hydrographiques anciennes. Mais c'est justement ici que l'intelligence pénétrante de Cortez a indiqué les défauts de la projection longtemps avant Mercator."

For a reproduction of the title page and of the twelve-page text of Martin Cortez's "Breve Compendio," see G. Hellmann, "Neudrucke," 1898, No. 10.

REFERENCES.-Fernandez de Navarrete, "Disertacion sobre la historia de la nautica y de las mathematicas," Madrid, 1846; "La Grande Encyclopédie," Vol. XII. p. 1114; Biographie Générale," Vol. XI. p. 964; Gilbert, De Magnete, Book I. chap. i.; Book III. chap. i. and Book IV. chap. i.

Costæus, Joannes-Giovanni Costeo-of Lodi, who died at Bologna in 1603, was an Italian physician teaching medicine at the Universities of Turin and of Bologna and the author of several valuable works, notably the "Tractatus de universali stirpium natura," Turin, 1578; the "Disquisitionum physiol. . . . Avicennæ sectionem," Bologna, 1589; the "Annot. in Avicennæ canonem . Venetia, 1595; and the "De igneis medicinæ . . published also at Venice in the last-named year.

Gilbert, who speaks of him (De Magnete, Book I. chap. i.; Book II. chap. iii.; Book VI. chap. v.) gives this as the theory propounded by Costaus regarding the powers of amber and loadstone: "There is work on both sides, result on both sides, and therefore the motion is produced in part by the loadstone's attraction and in part by the iron's spontaneous movement; for, as we say that the vapours given out by the loadstone do by their own nature haste to attract the iron, so, too, do we say that the air impelled by the vapours, while seeking a place for itself, is turned back, and when turned back impels and transfers the iron, which is picked up, as it were, by it, and which, besides, is exerted on its own account. In this way, there is found a certain composite movement, resulting from the attraction, the spontaneous motion and the impulsion; which composite motion, however, is rightly to be referred to attraction, because the beginning of this motion is invariably from one term, and its end is there too; and that is precisely the distinguishing character of attraction."

REFERENCES.-Eloy (N. F. J.), "Dict. historique de la Médecine "; Larousse, Dict. Univ.," Vol. V. P. 245.

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Cusanus-Nicolas Khrypffs or Krebs, Cardinal de Cusa (1401– 1464), an eminent German scholar, who, abandoning the study of law, entered the Church, became Archdeacon of Liége, member of the Council of Basle, and was raised, in 1448, to the dignity of Cardinal. His biographer in the ninth "Encycl. Britan." (Vol. VI. pp. 728-729) says: "As in religion he is entitled to be called one of the Reformers before the Reformation, so, in philosophy, he was one of those who broke with scholasticism while it was still the orthodox system." His works were published in complete form by H. Petri, 1565.

REFERENCES.-Hartzheim (Josephus), "Vita N. de C.," Trèves, 1730; Deux (M.), "Life of C. Cusa," 1847; Scharpff (Franz Anton), "Der Cardinal und Bischof Nic. von Cusa . Tübingen, 1871;

Dr. W. Windelband, History of Philosophy," auth. tr. by Jas. H.
Tufts, New York, 1893, pp. 345-347; Humboldt, "Cosmos," 1860, Vol. II;
Libri (G.), “ Hist. des Sciences Mathém.," Vol. III. p. 99; Dr. F. Ueber-
weg, History of Philosophy," tr. by Geo. S. Morris, 1885, Vol. II. pp. 23–
24; Ritter (Dr. Heinrich), Geschichte der Phil.," Vol. IX. p. 142;
Gilbert, De Magnete, Book I. chap. i. and Book II. chaps. iii. xxxvi.;
Journal des Savants for January 1894; Houzeau et Lancaster,
Bibl. Gén.," Vol. II. p. 115; Larousse, Dict. Univ.," Vol. V. p. 687;
Biogr. Gén.," Vol. XII. pp. 651-657.

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Dominicus, Maria Ferrariensis-" Novara "-Italian savant (1464-1514), taught astronomy at Bologna, Rome and elsewhere, and had for one of his pupils the celebrated Copernicus, who, later on, became an associate in his investigations. None of his writings have reached us.

Gilbert thus alludes to Dominicus as well as to Stadius at Chap. II. book vi. of his De Magnete: "According to Dominicus Maria's observations, the north pole is raised higher and the latitudes of places are greater now than in the past: from this he infers a change of latitudes. But Stadius, holding the directly opposite opinion, proves by observations, that the latitudes have grown less. 'The latitude of Rome,' says he, 'is given in the Geographia of Ptolemy as 41°; and lest any one should say that some error has crept into the text of Ptolemy, Pliny relates, and Vitruvius in his ninth book testifies, that at Rome on the day of the equinox the ninth part of the gnomon's shadow is lacking. But recent observation (as Erasmus Rheinhold states) gives the latitude of Rome in our age as 41°; so that you are in doubt whether one-half of a degree has been lost (decrevisse) in the centre of the world, or whether it is the result of an obliquation of the earth.''

REFERENCES.-Borsetti (Ferrante Giovanni), “Hist. Gymn. Ferrar.," Vol. II. p. 50; Tiraboschi (Girolamo), "Storia della Letteratura Italiana," Vol. XIV. p. 296; Montucla (J. F.), "Hist. des Math.," Vol. I. p. 549; Houzeau et Lancaster, Bibl. Gén.," Vol. II. pp. 215-216; Biog. Gén.," Vol. XXXVIII. p. 336.

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Dupuis. See Putaneus.

Empedocles, whom Gilbert merely names in Book V. chap. xii. of De Magnete, was a native of Sicily, distinguished as a philosopher as well as for his knowledge of medicine and of natural history.

Empedocles flourished about the year 442 or 460 B.C., and was pupil of Pythagoras or Anaxagoras, and, as others say, of Parmenides (“The Metaphysics of Aristotle," by the Rev. John H. McMahon, London, 1857, pp. 19-20, 34, 118).

"Rien n'est engendré, disait Empédocle, rien ne périt de la mort funeste. Il n'y a que mélange ou séparation de parties. . L'éclair, c'est le feu s'échappant du nuage où le soleil l'avait lancé. La foudre n'est qu'une plus grande quantité de feu. Le tonnerre, c'est ce même feu qui s'éteint dans le nuage humide. . . . Les phénomènes magnétiques viennent de la convenance parfaite des pores et des effluves de l'aimant et du fer. Dès que les effluves de l'aimant ont chassé l'air que contenaient les pores du fer, le courant des effluves de fer devient si fort que la masse entière est entrainée ("Dict. des Sc. Philos.," Paris, 1852, Vol. II. pp. 206-214).

REFERENCES.-Karsten, "Emped. Agrig. Carmin. Reliq." in Vol. II of "Phil. Graec. vet. relig.," Amst., 1838; and the extensive list of authorities cited in Larousse, "Dict. Univ.," Vol. VII. pp. 457458; Houzeau et Lancaster, Bibl. Gén.," Vol. I. part i. p. 401; Ueberweg, "Hist. of Philos." (Morris), 1885, Vol. I. pp. 60-63; The Works of George Berkeley," by A. C. Fraser, Oxford, 1901, Vol. III. pp. 205, 247, 254, 290; Paul Tannery, "Pour l'histoire de la Science Hellène," Paris, 1887, Chap. XIII. pp. 304-339; "Greek Thinkers,' by Theodor Gomperz, tr. of L. Magnus, London, 1901, Chap. V. pp. 558562, 601; "A History of Classical Greek Literature," by Rev. John P. Mahaffy, New York, 1880, Vol. I. pp. 123–128; Vol. II. pp. 48, 73, 77; "Essai Théorique et Historique sur la génération des connaissances humaines," par Guillaume Tiberghien, Bruxelles, 1844, Vol. I. pp. 185–187.

We are told by Alex. Aphr. (Quæst. Nat., II. 23, p. 137, Speng) that, like Empedocles, Democritus sought to explain the attractive power of the magnet, upon which the latter wrote a treatise. (according to Diog. IX. 47).

Democritus was born at Abdera in Thrace about 470 or 460 B.C., and, according to Thrasyllus, the grammarian, he died 357 B.C.— the same year as Hippocrates. He was considered, by far, the most learned thinker of his age, and, according to Carl Snyder, who dedicates "The World Machine," 1907, to Democritus, he was justly esteemed by Bacon as the mightiest of the ancients, for he wrote illuminatively upon almost every branch of natural knowledge.

The following note to "The Atomistic Philosophy" appears at p. 230, Vol. II of Dr. E. Zeller's "History of Greek Philosophy," translation of S. F. Alleyne, London, 1881: