JACQUES DOMINIQUE

CASSINI  , Count (1748-1845), son of Cesar Francois Cassini, was born at the observatory of Paris on the 3oth of June 1748 . He succeeded in 1784 to the directorate of the observatory; but his plans for its restoration and re-equipment were wrecked in 1793 by the animosity" of the National Assembly . His position having become intolerable, he resigned on the 6th of September, and was thrown into prison in 1794, but released after seven months . He then withdrew to Thury, where he died, aged ninety-seven, on the 18th of October 1845 . He published in 1770 an account of a voyage to America in 1768, undertaken as the commissary of the Academy of Sciences with a view to testing Pierre Leroy's watches at sea . A memoir in which he described the operations superintended by him in 1787 for connecting the observatories of Paris and Greenwich by longitude-determinations appeared in 1791 . He visited England for the purposes of the work, and saw William Herschel at Slough . He completed his father's map of France, which was published by the Academy of Sciences in 1793 . It served as the basis for the Atlas National (179,), showing France in departments . Count Cassini's Memoires pour servir a l'histoire de l'observatoire de Paris (181o) embodied portions of an extensive work, the prospectus of which he had submitted to the Academy of Sciences in 1774 . The volume included his 'Doges of several academicians, and the autobiography of his great-grandfather, the first Cassini . See J .

F . S . Devic, Histoire de la

vie et des travaux de J . D . Cassini (1851); J . Delambre, Histoire de l'astronomie au XVIII' siecle, pp . 309-313; Phil . Mag . 3rd series, vol. xxviii. p . 412; C . Wolf, Histoire de l'observatoire de Paris (1902), p . 234 et passim .

(A . M .