CA:SAR Fnexcts CASSINI, son of James, was born at Paris, June 17, 1714. He is generally known by the name of Cassini de Thury, having been the first to take a territorial appellation from the estate acquired by his father or grandfather. lie accompanied his father during his geodesical operations in 1733, and was received member of the Academy at the age of 21. Ile succeeded his father as director of the observatory and as maitre des comptea, and died September 4, 1784, of smallpox. His most remarkable labour is the large triangulation of France, pub lished in 1744, under the title of ' Ls M6ridionne, ke., verifi6e, Paris. He nearly completed the large map of France, of which his son presented 121 thetas to the National Assembly in 1799. Ile made along anccesaion of observations at the observatory; but these, though they would have done credit to Dominic) Cassini, were too late of their kind. The time was past in which a descendant of the first two Cassinis could compete with tho rest of the world by his hereditary means only. We must refer to Lalande's 'Bibliographic' for A list of his writings, and to Delambre Hiatoiro de l'Aatronomie xviii. Sikle ') for detail upon his astronomical observations.
Joust DOMINIC! CASSINI, son of Cassiui de Thnry, and most com monly known by hi, title of Count, was born at Paris June 30, 1748, and died in the same city October 17, 1345. He is the first of his family who decidedly adopted the system of Newton, though the aamo may perhaps be said of Cassini de Thury, from some isolated psasagea in his writings. Ho was (sleeted member of tho Academy in 1770, in
which year ho published the account of a voyage made by order of the king for trial of the chronometers of Le Roy. lie was employed in 1787 with M6chain and Legendre In the operations for the junction of the observatories of Paris and Greenwich by a chain of triangles. lie made repeated endeavours to induce the government to re-establish the observatory upon a new footing and with large instruments. The National Convention, apparently with the desire to force him to resign, resolved in 1793 that the observatory should be placed no longer under the control of one person, but of four, who should take annual duty in rotation. Of the four the Count Cassini was one, and the other three were his own pupils. To this lie refused to submit, and resigned his charge September 6, 1793. He received an order to quit the observatory in twenty-four hours, and In tho following year was imprisoned for seven months. From that time he abandoned astronomy entirely, refusing either to take part in the great survey, or to belong to the Bureau dee Longitudes, or to the Institute, though he entered the latter body under the empire. lie fixed himself ou his own estate, and devoted himself to the duties of the Conseil of his department.