xxiv CONTENTS. 



satellites; Comets; Light of the heavenly bodies, 421. Planetary worlds ; Fon- 

 tenelle; Mercury; Venus, 422. Moon; Mars, 423. Newly discovered planets; 

 Jupiter ; Saturn ; Georgian planet, 424, 425. 



LECTURE XLV. 



ON PRACTICAL ASTRONOMY, 425. 



Real motions neglected ; Situation of a point in the heavens, 425. Meridian ; 

 Astronomical instruments; Time; Sidereal day; Solar day; Equation of time, 

 426. Dialling ; Chronology ; Calendar, 427. Improvement suggested ; Repub- 

 lican calendar ; Metonic cycle, 428. Golden number ; Epact ; Moon's age ; 

 Julian period ; Astronomical time ; Quadrants ; Transit instruments, 429. 

 Hadley's quadrant ; Declinations ; Refraction and parallax ; Latitudes, 430. 

 Longitudes ; Lunar observations ; Distance of the sun, 431. Transits; Densities 

 of the sun and planets ; Artificial globe, 432. Planispheres ; Orreries, 433. 



LECTURE XLVI. 



ON GEOGRAPHY, 435. 



Particular account of the earth ; Curvature of its surface ; Direction of the 

 plumb line; Ellipticity, 435. Measurements of degrees ; Zones, 436. Climates; 

 Sea and land ; Continents, 437. Rivers ; Elevations ; Mountains, 438. Dif- 

 ferent orders of mountains, 439. Internal parts of the earth ; Density of the 

 earth, 440. 



LECTURE XL VII. 



ON THE TIDES, 441. 



Tides noticed by the ancients, 441. Daily changes ; Monthly changes ; 

 Yearly changes ; Connexion with the moon ; Effect of gravitation on a fluid 

 sphere, 442. Primitive lunar tides ; Comparison with a pendulum ; Direct and 

 inverted tides, 443. Tides of a lake; Resistance; Tides of the Atlantic, 444. 

 Particular modifications, 445. Tides of the channels and of rivers; Inferior and 

 superior tides, 446. Laws of elevation and of depression ; Mode of observing 

 the tides ; Solar tides ; Combination of tides ; Retardation of spring and neap 

 tides, 447. Increased height in converging channels, 448. Combinations in 

 particular ports ; Currents, 449. Tides of the atmosphere, 450. 



LECTURE XLVIII. 



ON THE HISTORY OF ASTRONOMY, 451. 



Earliest astronomy; Signs of the zodiac, 451. Babylonian observations ; Chal- 

 deans; Hermes; Egyptians; Chinese; Indians, 452. Greeks; Thales; Pytha- 

 goras, 453. Meto ; Alexandrian school ; Eratosthenes ; Hipparchus, 454. 

 Ptolemy, 455. Arabians ; Persians ; Copernicus, 456. Tycho Brahe ; Kepler, 

 457. Napier ; Huygens ; Cassini ; Gravitation, 458. Newton's discoveries ; 

 Extract from Pemberton, 459. British astronomers ; Observatory at Greenwich, 

 460. Determinations of the longitude; Late discoveries, 461, 462. Chrono- 

 logical table, 463. 



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