The work of William Herschel--His discovery of Uranus--His discovery
that the stars are suns--His conception of the universe--His deduction
that gravitation has caused the grouping of the heavenly bodies--The
nebula, hypothesis,--Immanuel Kant's conception of the formation of the
world--Defects in Kant's conception--Laplace's final solution of the
problem--His explanation in detail--Change in the mental attitude of the
world since Bruno--Asteroids and satellites--Discoveries of Olbersl--The
mathematical calculations of Adams and Leverrier--The discovery of the
inner ring of Saturn--Clerk Maxwell's paper on the stability of Saturn's
rings--Helmholtz's conception of the action of tidal friction--Professor
G. H. Darwin's estimate of the consequences of tidal action--Comets
and meteors--Bredichin's cometary theory--The final solution of the
structure of comets--Newcomb's estimate of the amount of cometary dust
swept up daily by the earth--The fixed stars--John Herschel's studies
of double stars--Fraunhofer's perfection of the refracting
telescope--Bessel's measurement of the parallax of a star,--Henderson's
measurements--Kirchhoff and Bunsen's perfection of the
spectroscope--Wonderful revelations of the spectroscope--Lord Kelvin's
estimate of the time that will be required for the earth to become
completely cooled--Alvan Clark's discovery of the companion star of
Sirius--The advent of the photographic film in astronomy--Dr. Huggins's
studies of nebulae--Sir Norman Lockyer's "cosmogonic guess,"--Croll's
pre-nebular theory.