626

INDEX.

for determining- tlie length of the seconds’pendulum, 155; investigates the influenceof the resistance of the air on the rate ofoscillation, ib.; directs his attention tothe irregularities of Uranus , 167; re-searches on the elements of Saturn ’s ring,259; determines the period of the cometof 1811,289; observations on the nucleusof Halley’s comet, 294; opinion respect-ing the tails of comets, 311; researcheson the quantity and laws of precession,320; researches on refraction, 335;method for facilitating the reduction ofobservations, 334; zone observations ofstars, 511; determines the parallax of61 Cygni, 551; researches on the motionof the solar system in space, 556.

Bianchini—Researches on the rotation ofVenus , 234.

Biot—Experiments with the pendulum, 153;value of the terrestrial ellipticity hencededuced by him, 153; researches on themotion of the solar system in space, 556.

Bode—Explanation of the solar spots, 222.

Bond—Physical observations of Saturn ’sring, 265 ; discovers the eighth satellite ofSaturn , 271.

Borel—Account of the invention of thetelescope, 517.

Borelli—his ideas of circular motion, 20 ;surmise respecting the orbits of comets, 102.

Bouguer—Researches on atmospheric refrac-tion, 328.

Bouillaud—determines the period of thevariable star Mira Ceti, 540; opinion re-specting the cause of its variable bright-ness, 541.

Bouvard—his determination of the mass ofJupiter , 130; publishes tables of Jupiter and Saturn , 131; determines the mass ofUranus , 132; calculates tables of Uranus ,165; finds it impossible to reconcile theancient with the modern observations, ib. ;suspects the existence of an exterior planet,ib.

Bouvard, E.—calculates tables of Uranus ,174; finds it impossible to reconcile themwith all the observations of theplanet, 175.

Bradley—Researches on the satellites of Ju­ piter , 81; 'first introduces the equation oflight into the tables of these bodies, ib .;discovers the great inequality of the threeinterior satellites, and suggests its physicalcause, 82; discovers that the orbit of thefourth satellite is eccentric, ib.‘, researcheson refraction, 329; discovers the aberra-tion of light, 338; discovers the nutationof the earth's axis, 341; accounts of hislabours at the Observatory of Greenwich,483; remark respecting the parallax ofthe fixed stars, 549; remark relative tothe motion of the solar system in space,554.

Brahe , Tycho—overthrows the theory ofsolid orbs, 15; demonstrates that comets

are situate beyond the moon’s orbit, 102;supposes them to move in circular orbits,ib. ; views respecting the tails of comets,308 ; first employs refraction in correct-ing astronomical observations, 321; in-vents the mural quadrant, 445; observesthe new star which appeared in the year1572, 539; opinion respecting its origin,ib. ; estimate of the apparent diameters ofthe stars, 547.

Brewster—his opinion respecting the solarspots, 227.

Brinkley—Researches on refraction, 332;researches on the parallax of the fixedstars, 550.

Burchardt—calculates the terms of the longinequality of Jupiterand Saturn, depend-ing on the fifth powers of the eccentricitiesand inclinations, 129; calculates the ele-ments of Halley’s comet for 1759, 137;calculates the lunar parallax by means ofthe formulas of Laplace, 228.

Burg—calculates tables of the moon, 118;discovers irregularities in the moon’s epoch,il.; attempts to represent them by anempiric equation, 119.

Campani—attains great excellence in theconstruction of refracting telescopes, 526.

Oapocci—Researches on the comet of 1843,290.

Carlini—Researches on the lunar theory,119; experiments with the pendulum forthe purpose of determining the mean den-sity of the earth, 160.

Cassini, J. D.—Discovers the coincidence ofthe nodes of the moon’s orbit with thoseof the moon’s equator, 73; publishes tablesof Jupiter ’s satellites at Bologna, 80; re-jects the equation of light, ib. ; method fordetermining the solar parallax, 211;value of that element assigned by him,212; remarks respecting the solar spots,219; executes a chart of the moon’s sur-face, 230; observes an occultation ofJupiter by the moon, 231; researches onthe physical constitution of Venus , 234;discovers that she has a rotatory motion,ib.; determines the period of rotation,ib.; observations on the physical constitu-tion of Mars , 236; discovers that it revolveson an axis, ib.; determines the time of rota-tion, ib.; researches on the rotation ofJupiter , 244; theory of the belts of Ju­ piter , 248; discovers the duplicity ofSaturn ’s ring, 260; physical observationsof the ring, 263; discovers four satellitesof Saturn , 268; variable brightness of thefifth satellite, 271; hypothesis of atmo-spheric refraction, 322; appointed Directorof the Royal Observatory of Paris, 457-

Cassini, J.—his remarks on the rotation ofVenus , 234; views respecting the visi-bility of the stars, 543; attempts to de-termine the apparent diameter of Sirius,