INDEX.

Aberration of Light —discovered by Brad-ley, 338; various determinations of itsmaximum value, 340.

Adams—Researches on the theory of Uranus ,168; transmits his results to the Astro-nomerRoyal,173; they furnish the earliestindication of the Trans-Uranian planet, ib .;second series of results obtained by him,185; announcement of his researches by Sir John Herschel , 194.

Airy—Researches on the lunar theory, 120;discovers the long inequality in the Earth and Venus, 127; determines the mass ofMars , 129; researches on the mass of Ju­ piter , 130; determines the ellipticity of theEarth , 145; measures an arc of longitudein the British Isles , 150; demonstrates theexistence of errors in the tabular radiusvector of Uranus , 167; receives fromAdams the results of his researches on theexistence of an exterior planet, 173; hisreply to Adams, 174; correspondence withLe Verrier on the theory of Uranus , 184;reply of the latter, ib. ; proposes a searchfor the planet, ib.', announces to Le Ver­ rier the results arrived at by Adams, 194;communicates an historical statement re-specting the discovery of the Trans-Ura-nian planet, 196; detects two new ine-qualities in the motion of the moon, 206;determination of the lunar parallax, 229;modification of Bessel’s method for facilitat-ing the reduction of observations, 345; suc-ceeds Pond at the Observatory of Green-wich, 493; reduction of the Lunar andPlanetary Observations, 495; introducesthe use of an altitude and azimuth instru-ment at the Greenwich Observatory, ib. ;transit circle, 497; reflex zenith telescope,499; Cambridge Catalogue of Stars, 513;first Greenwich Catalogue, ib.; secondGreenwich Catalogue, 514; physical ex-planationofthedisksandringsofstars, 546. j

A1 Batani—discovers the motion of the aphe-lion of the terrestrial orbit, 9 7.

Altitude and Azimuth Instrument—firstusedby Roemer, 465. j

Apian—first suggests the use of coloured ;glasses in observations of the sun, 227; re- jmarks that the tails of comets are turned 'opposite to the sun, 297. ;

Arago—Remarks respecting the discovery ofthe planet beyond Uranus , 196; observesoccultations of small stars by the moon,230; phenomeon witnessed by him onthose occasions, 231; experiments on thelight of comets, 313; account of the solareclipse of 1842, 368.

Arcs of the Meridian—Measurement of thearc between Gottingen and Altona, 144;arc of India , 145; arc measured by La-caille at the Cape of Good Hope , 147; la-bours of Maclear, 148; arc measured inthe British Isles , 149.

Argelander—Zone observations of stars, 511;executes a catalogue of stars, 513; re-searches on stars having a variable bright-ness, 541; researches on the motion of thesolar system in space, 556,

Atmosphere, terrestrial—Researches on theoscillations of the, 163,

Attraction—Ideas of Copernicus on the sub-ject of, 15; Gilbert, 16; Kepler, 17;Galileo , 19; Borelli, 20; researches ofNewton, 20-40; experiments of Bouguer,158; Schehallien experiment, ib.

Auzout—his remark respecting a twilight inthe moon, 232; invents the micrometer,450.

Bacon, Roger—Ideas of the telescope, 517.

Baily—Researches on the influence of the airin pendulum experiments, 156; determinesthe mean density of the earth, 159; phe-nomena observed during the annulareclipse of 1836, 409; labours connectedwith star catalogues, 508-13.

Bailly—explains the origin of the libratorymotion of the nodes of the second satelliteof Jupiter , 86; researches on the physi-cal theory of the satellites, 88; determinesthe magnitude of Jupiter ’s satellites, 250.

Ball—discovers the duplicity of Saturn ’sring before the same phenomenon was re-marked by Cassini, 526.

Battista Porta—Ideas of the telescope, 518.

Bernouilli—his researches on the tides, 71.

Bessel—his researches on the mass ofSaturn , 131; experiments on the attrac-tion of different bodies, 133; researches onthe satellites of Saturn , 142; investigatesthe ellipticity of the earth, 145; methodS S