igures of the celestial bodies. In the fourth book he considers the
oscillations of the ocean and the atmosphere, arising from the
disturbing action of the celestial bodies. The fifth book is devoted to
the investigation of the movements of the celestial bodies around their
centres of gravity. In this book the author gives a solution of the
great problems of the precession of the equinoxes and the libration of
the moon, and determines the conditions upon which the stability of
Saturn's ring depends. The sixth book is devoted to the theory of the
planetary movements; the seventh, to the lunar theory; the eighth, to
the theory of the satellites of Jupiter, Saturn, and Uranus; and the
ninth, to the theory of comets. In the tenth book the author
investigates various subjects relating to the system of the universe.
Among these may be mentioned the theory of astronomical refractions;
the determination of heights by the barometer; the investigation of the
effects produced on the movements of the planets and comets by a
resisting medium; and the determination of the values of the masses of
the planets and satellites. In the six books forming the fifth volume of
the work, the author, besides presenting his readers with an historical
exposition of the labours of Newton and his successors on the theory of
gravitation, gives an account of various researches relative to the
system of the universe, which had occupied his attention subsequently to
the publication of the previous volumes. In the eleventh book he
considers the subjects of the figure and rotation of the earth. In the
twelfth book he investigates the attraction and repulsion of spheres,
and the laws of equilibrium and motion of elastic fluids. The thirteenth
book is devoted to researches on the oscillations of the fluids which
cover the surfaces of the planets; the fourteenth, to the subject of the
movements of the celestial bodies around their centres of gravity; the
fifteenth, to the movements of the planets and comets; and the
sixteenth, to the movements of the satellites. The author published a
supplement to the third volume, containing the results of certain
researches on the planetary theory, and a supplement to the tenth book,
in which he investigates very fully the theory of capillary attraction.
There was also published a posthumous supplement to the fifth volume,
the manuscript of which was found among his papers after his death.

JOSEPH FOURIER.

BIOGRAP