CONTENTS

BOOK I

CHAP.
1. Summary of subject-matter of meteorology.
2. The material and the efficient cause of the phenomena to be studied.
3. The position of air and fire relatively to the celestial sphere. Why clouds and water do not form in ether.
4. The cause of shooting-stars and the like.
5. The cause of the appearance of chasms, &c., in the sky.
6. Refutation of earlier theories of comets.
7. The cause of comets.
8. The milky way.
9. The causes of rain, and the difference between cloud and mist.
10. The causes of dew and hoar-frost.
11. The causes and concomitants of snow.
12. Hail—where and when it is produced.
13. Winds, rivers, and springs.
14. Why the same parts of the earth are not always watered by rivers, or always dry. Floods.

BOOK II

1. Three theories of the origin of the sea. It cannot have springs. Why it flows as it does.
2. Its place. It is the end rather than the beginning of water. Why it is not increased by the influx of rivers.
3. Why is it salt? Is it eternal? The cause of different tastes and colours in water.
4. The causes of winds.
5. Why winds blow at some times and not at others. From where, and when, each wind blows.
6. The direction of the winds; which are contrary; and which can blow together. Their number, concomitants, and natures.
7. Three theories of earthquakes.
8. The causes of earthquakes. Indications that they are due to exhalation.
9. Early theories of thunder and lightning.