ivision in
Saturn's ring (see SATURN); made the earliest sustained observations of
the zodiacal light, and published, in _Les Elements de l'astronomie
verifies_ (1684), an account of Jean Richer's (1630-1696) geodetical
operations in Cayenne. Certain oval curves which he proposed to
substitute for Kepler's ellipses as the paths of the planets were named
after him "Cassinians." He died at the Paris observatory on the 11th of
September 1712.

A partial autobiography left by Giovanni Domenico Cassini was
published by his great-grandson, Count Cassini, in his _Memoires pour
servir a l'histoire des sciences_ (1810). See also C. Wolf, _Histoire
de l'observatoire de Paris_ (1902); Max. Marie, _Histoire des
sciences_, t. iv. p. 234; R. Wolf, _Geschichte der Astronomie_, p.
450, &c.

JACQUES CASSINI (1677-1756), son of Domenico Cassini, was born at the
Paris observatory on the 8th of February 1677. Admitted at the age of
seventeen to membership of the French Academy of Sciences, he was
elected in 1696 a fellow of the Royal Society of London, and became
_maitre des comptes_ in 1706. Having succeeded to his father's position
at the observatory in 1712, he measured in 1713 the arc of the meridian
from Dunkirk to Perpignan, and published the results in a volume
entitled _De la grandeur et de la figure de la terre_ (1720) (see
GEODESY). He wrote besides _Elemens d'astronomie_ (1740), and died on
the 18th of April 1756 at Thury, near Clermont. The first tables of the
satellites of Saturn were supplied by him in 1716.

See C. Wolf, _Histoire de l'observatoire de Paris_; Max. Marie,
_Histoire des sciences_, vii. 214; R. Wolf, _Geschichte der
Astronomie_, p. 451; J.C. Houzeau, _Bibl. astronomique_; J. Delambre,
_Histoire de l'astronomie au XVIII'e siecle_, pp. 250-275 (unfairly
depreciatory); J.F. Montucla, _Hist. des mathematiques_, iv. 145, 248.

CESAR FRANCOIS CASSINI, or CASSINI DE THURY (1714-1784), son of Jacques
Cassini, was born at the observatory of Paris on the 17th of June 1714.
He succeeded to his father's official employments, continued the
hereditary surveying operations, and began in 1744 the construction of a
great topographical map of France. The post of director of the Paris
observatory was created for his benefit in 1771, when the establishment
ceased to be a dependency of the Academy of Sciences. Cassini de Thury
died at Thury on the 4th of September 1784. His chief works
are:--_Meridienne d