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CONTENTS. 



THE PLANETS : ARE THEY INHABITED WORLDS ? 



PACK 



CHAP. I. 1. Aspect of the firmament. 2. Direct evidence on this 

 question not obtained by the telescope. 3. Telescope diminishes 

 distance. 4. Evidence from analogy extremely cogent. 5. Con- 

 sideration of the terrestrial planets. 6. Circumstances which 

 render the earth habitable. 7. Like circumstances to be looked 

 for in the planets. 8. Similarity of position and motion of 

 terrestrial planets. 9. Uniformly supplied with light and heat. 

 10. Objection of inequality of distance answered. 11. By the 

 effect of atmosphere. 12. Different degrees of light on the planets. 

 13. Structure of the eye. 14. Its adaptation to different dis- 

 tances. 15. Adaptation of strength of organised creatures to 

 their weight. 16. Adaptation of the rotation of the earth to this 

 organisation . 1 7. Floral clock of Linnaeus. 1 8. Time of rotation 

 not the consequence of a physical law. 19. Rotation of the other 

 planets. 20. Of Mara. 21. Of Yenus and Mercury. 22. Their 

 close analogy to the earth. 23. Inclination of the earth's axis. 

 24. Produces the seasons. 25. Like provision in the other 

 planets. 26. The atmosphere 1 



CHAP. II. 1. Uses of an atmosphere colour of sky. 2. Its effects 

 on temperature. 3. Planetary atmospheres observable. 4. 

 Clouds visible in them. 5. Hence rain, hail, and snow. 6. 

 Winds manifested on the planets. 7. Clouds on Mercury, Venus, 

 and Mars. 8. Continents and oceans. 9. Effect of gravity on 

 planets. 10. Its relation to organised beings. 11. Adaptation 

 of organised beings to the force of gravity 12. Gravity on 

 Mercury, Venus, and Mars. 13. Solar system. Planets. 14. 

 Number of planets groups. 15. Inner group the twenty-five 

 grouped round the sun. 16. The outer group Jupiter, Saturn, 

 Uranus, and Neptune. 17. Their distances from the sun, from 

 each other, and from the earth. 18. Apparent diameters of Sun's 

 disk as seen from these planets Sun's light and heat. 19. 

 Question of habit-ability of these planets considered in reference 

 to sun's light and heat. 20. Great comparative magnitude of 



