The Bernoulli family is as well known in the history of mathematics, by the distinguished services of eight of its members, as is the Cassini family through the successes achieved by four of its representatives in the development of astronomical studies.
Daniel Bernoulli (1700–1782), second son of John I, constructed a dipping needle, which is described on p. 85 of the Eighth “Britannica,” Vol. XIV, and with which he observed the dip to diminish half a degree during an earthquake in the year 1767. Before Daniel was twenty-four years old he had declined the Presidency of the Academy of Sciences at Genoa, and, at the age of twenty-five, was appointed Professor of Mathematics at St. Petersburg.
John Bernoulli II (1710–1790), youngest of the three sons of John I, gained three prizes from the French Academy of Sciences for Memoirs on the Capstan, on the Propagation of Light and on the Magnet.
John Bernoulli III (1744–1807), grandson of John I, took the degree of Doctor of Philosophy at the age of thirteen, and, when nineteen years old, was appointed Astronomer Royal of Berlin. He published several volumes of travels, in one of which he relates (A. L. Ternant, “Le Télégraphe,” 1881, p. 32) that he saw, in the last-named city, an instrument constructed of five bells, with which all letters of the alphabet could be expressed.
James Bernoulli I (1654–1705), brother of John I, while at London, was introduced into the philosophical meetings of Boyle, Hooke, Edward Stillingfleet and other learned and scientific men. He opened, in 1682, the Collegium Experimentale Physico-Mechanicum for public instruction, but his lasting fame dates from the year 1684, when the great Von Leibnitz published his treatise “De Gravitate Ætheris.” Three years later, in 1687, James occupied the mathematical chair of the University of Basel, made vacant by the death of the learned Megerlin.
References.—Whewell, “Hist. of the Inductive Sciences,” 1859, Vol. I. pp. 358–366, 375–380, 393, 430, and Vol. II. pp. 32–39, 42; “Hist. de l’Acad. Royale des Sciences,” 1700–1707; Edin. “Encycl.,” 1813, Vol. III. pp. 464–470; “Med. Library and Historical Journal,” New York, 1903, Vol. I. pp. 270–277.
For Bernoulli family see “Histoire des Sc. Math. et Phys.,” Maxim. Marie, Paris, 1888, Vols. VII-XI; “Geschichte der Mathemathik,” Moritz Canton, Leipzig, 1898, Vol. III. pp. 207–261; “Histoire Générale des Mathématiques,” Chas. Bossut, Paris, 1810, Vol. II. s. 2, as at table, p. 512. See the family tree in “Eng. Cycl.,” Vol. VI. p. 972, and all the Bernoullis at p. 84 of Vol. II, Houzeau et Lancaster’s “Bibl. Gén.,” 1882.
A.D. 1700.—Morgagni (Giovanni Battista), while practising medicine at Bologna and at Venice, uses the magnet to remove particles of iron which had accidentally fallen into the eyes, exactly in the same manner as Kirkringius and Fabricius Hildanus had done before him.
References.—Maunder’s “Biog. Treasury”; also Beckmann’s “History of Inventions,” Vol. I. p. 44, and biography in Larousse, Vol. XI, as well as in Vol. XVI of the Ninth “Britannica.”
A.D. 1700.—Duverney (Joseph Guichard), an eminent French anatomist, knew at this date that the limbs of a frog are convulsed by the electric current (as shown in the “Histoire de l’Académie des Sciences,” 1700, p. 40, and 1742, vol. I. p. 187), and the Italian physician L. Marco Antonio Caldani, assistant to Morgagni, alludes to the “revival of frogs by electrical discharges.”