REFERENCES.--Michaud, “Biog. Univ.,” Vol. XLV. p. 340; Dr. John Thomas, “Universal Pron. Dict.,” 1886, p. 2514; Brunet, “Manuel du Libraire,” Vol. V. p. 1519. =A.D. 1700.=--Bernoulli (John I), son of Nicolas, the founder of the celebrated family of that name, improves upon Picard’s discovery of the electrical appearance of the barometer, made A.D. 1675, by devising a mercurial phosphorus or mercury shining _in vacuo_ (“Diss. Physica de Mercurio Lucente,” etc., Basel, 1719). This procured the favourable notice of King Frederick I, of Prussia, who rewarded him with a medal. John Bernoulli I (1667–1748) was a member of nearly every learned society of Europe and “one of the first mathematicians of a mathematical age.” His exceedingly valuable memoirs, found in all the scientific transactions of the day, were first collected in their entirety during the year 1742, by Cramer, Professor of Mathematics, and published at Lausanne and Geneva. “Is it not surprising,” remarks Prof. Robison, in his able article on “Dynamics” (Eighth “Britannica,” Vol. VIII. p. 363), “that, twenty-five years after the publication of Newton’s ‘Principia,’ a mathematician on the Continent should publish a solution in the Memoirs of the French Academy, and boast that he had given the first demonstration of it? Yet, John Bernoulli did this in 1710. Is it not more remarkable that this should be precisely the solution given by Newton, beginning from the same theorem, the 40th I., Prin., following Newton in every step and using the same subsidiary lines? Yet, so it is.” This was five years after he had accepted (1705) the chair of mathematics made vacant by the death of his brother, James I. BERNOULLI FAMILY 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.