# Dictionary of National Biography, 1885-1900/Mendoza y Rios, Joseph de

​MENDOZA Y RIOS, JOSEPH de (1762–1816), astronomer, born on 15 Sept. 1762 (1764 is sometimes given) in the parish of St. Vincent, Seville, was eldest son of Don Joseph de Mendoza, a noble of Seville, by his wife Doña Maria Romana de Morillo. He was educated at the Royal College of Nobles, Madrid, where he displayed a marked taste for the exact sciences. On 30 April 1774 he was nominated cavalry cadet in the king's regiment of dragoons, but being anxious for a more active life he obtained on 12 April 1776 a lieutenant's commission in the Spanish navy. On 15 Dec. 1777 he sailed for the Philippines on board the Santa Inès, but the ship was taken by two English cruisers, and Mendoza was detained at Cork for a year. He then returned to Cadiz and stayed there until 1781, engaged upon important works, which the war between France, Spain, and England forced him to abandon.
By April 1782 he was captain (by brevet) of the Rosario, and in command of the second division of floating batteries sent against Gibraltar. On 1 Sept. he was gazetted aide-de-camp to the Duke de Crillon, an appointment which he held only a few days, for the attack failed, and he returned to Cadiz at the end of the month. He was made captain-lieutenant (‘lieutenant de vaisseau’), and spent his leisure in composing a treatise on navigation.
On 1 Jan. 1786 he became adjutant of the government of the port of Cadiz, and performed the duties until May 1787, when ill-health compelled him to return to Madrid. His treatise on navigation, which was published soon afterwards, brought much renown. The government made him captain of a frigate in 1789, and subsequently placed at his disposal three hundred thousand francs with which to form a maritime library by the purchase in England and France of books and instruments. Mendoza acquitted himself of this task with creditable zeal, and on 1 Feb. 1794 he was made brigadier of the royal navy.
Having been elected fellow of the Royal Society of London on 11 April 1793, he went to England for the purpose of being formally admitted in April 1797 (Thomson, Hist. of Roy. Soc. Append. iv. p. lxiii). Here he made so many friends and met with such liberal patronage, that he was in no hurry to return to Spain. In 1798 he forwarded to the Royal Hydrographic Museum at Madrid a choice collection of books and subjects. At length, determining to make England his home, he sent in his resignation to the Spanish government, and on 21 May 1800 his name was removed from the list of the Spanish navy.
The cost of Mendoza's publications was chiefly defrayed by liberal grants from the East India Company, the commissioners of longitude, the admiralty, and the corporation of Trinity House. Overwork at length told on him. He grew irritable and despondent, and having found in one of his tables a grave miscalculation, he shot himself at Brighton on 3 March 1815. About 1799 he married an Englishwoman, who had nursed him through a long illness, and by her he had two daughters, one of whom, Anna Fermina (1800–1857), became on 19 Jan. 1829 the wife of Sir Patrick Bellew, afterwards Lord Bellew (1798–1866) of Barmeath Castle, Dunleer, co. Louth (Burke, Peerage, 1891, p. 119).
Mendoza by his discoveries completely changed the bases of nautical astronomy. Among other eminent men, M. Biot has borne eloquent testimony to the simplicity and clearness of his methods.
To the ‘Philosophical Transactions’ for 1797 (pp. 43–122) he contributed a paper entitled ‘Recherches sur les principaux problèmes de l'astronomie nautique,’ and to the volume for 1801 (pp. 363–74) an elaborate essay, illustrated with diagrams, ‘On an Improved Reflecting Circle.’
His other writings are: 1. ‘Tratado de Navegacion,’ 2 vols. 4to, Madrid, 1787. 2. ‘Memoria sobre algunos Métodos nuevos de calcular la Longitud por las distancias lunares,’ &c., fol., Madrid, 1795. 3. ‘Coleccion de tablas para varios usos de la navegacion,’ fol., Madrid, 1800 (another edit., with supplementary tables, by J. J. Martínez de Espinosa y Tacon and J. Sánchez y Cerquero, 2 pts. 4to, Madrid, 1863). 4. ‘Tables for Facilitating the Calculations of Nautical Astronomy, … and several other Tables, useful in Astronomy and Navigation’ (‘Appendix, containing Tables for Clearing the Lunar Distances of Refraction and Parallax,’ by Henry Cavendish), 2 pts. 4to, London, 1801. 5. ‘A Complete Collection of Tables for Navigation and Nautical Astronomy,’ 4to, London, 1805, 2nd edit. 2 pts. 4to, London, 1809.
His portrait has been engraved.
[Mendoza et Navarrete, notices biographiques par M. Duflot de Mofras, Paris, 1845; Gent. Mag. 1816, pt. i. p. 372; Evans's Cat. of Engraved Portraits, ii. 277; Houzeau and Lancaster's Bibliographie Générale de l'Astronomie.]
G. G.