X GENERAL SUMMARY 



recorded by the annalists ; problematic obscurations, p. 379 (note 22). 

 Intensity of the light in the centre and at the edge of the Sun's disc 

 p. 387 (note 24, 25). Correlation of light, heat, electricity, and mag- 

 netism; Seebeck, Ampere, Faraday, p. 395. Influence of the Sun's spots 

 upon the temperature of our atmosphere, p. 390. 



II. The Planets: 



A. General comparative considerations: 

 a. Principal Planets : 



1. Number and epoch of discovery, p. 403. Names, planetary 

 days (week), and planetary hours, p. 408 (notes 13 and 14). 



2. Classification of the planets in two groups, p. 422. 



3. Absolute and apparent magnitudes ; configuration, p. 426. 



4. Order of the planets and their distances from the Sun ; the 

 so-called law of Titius ; old belief that the cosmical bodies 

 which we now see were not all visible from the beginning ; 

 Proselenes, p. 429, and notes 18 34. 



5. Masses of the planets, p. 445. 



6. Densities of the planets, p. 446. 



7. Periods of sidereal revolution and axial rotation, p. 448. 



8. Inclination of the planetary orbits and axes of rotation ; their 

 influence upon climate, p. 449 (note 42). 



J). Secondary planets, p. 457. 



B. Special consideration; enumeration of the individual planets and 

 their relation to the Sun as central body. 



The Sun, pp. 46770. 



Mercury, pp. 470473. 



Venus; spots, pp. 473 476. 



The Earth; numerical relations, pp. 476 477. 



The Moon of the Earth ; produces li^ht and heat ; ash-grey 

 or earth-light in the Moon ; spots ; nature of the Moon's 

 surface, mountains and plains, measured elevations ; pre- 

 vailing type of circular configuration ; craters of elevation 

 without continuing eruptive phenomena ; old traces of the 

 reaction of the interior upon the exterior (the surface) ; 

 absence of Sun and Earth tides, as well of currents as 

 transportive forces, on account of the want of a liquid 

 element ; probable geognostic consequences of these rela- 

 tions, pp. 477502. 



Mars ; ellipticity ; appearances of surface altered by change 

 of the seasons, pp. 502 504. 



The small planets, pp. 505 510. 



Jupiter : periods of rotation; spots and belts, pp. 511 515. 

 Satellites of Jupiter t pp. 515 517. 



