Imágenes de página
PDF
ePub

i8« The Water of Rivers contains many Particles of different Metals, Minerals, Sands, oleaginous and other Substances; as also certain subtile Spirits of Vitriol, Salt, Sulphur, &c.

19. 'The Rivers that have Gold-Sand enumerated.

20. The Waters of most- Rivers differ in Colour, Gravity, and other Qualities.

21. Certain Rivers are so inlarged, at stated Times, as to overflow their Banks.

22. To enumerate these Rivers, and their Causes.

23. To explain the Origin and Rife of Springs.

24- To find whether a Spring, or Well, may be made in a Place assigned. ,

25. To make a Well in a given Spot; if the Thing be possible.

26. To make an apparent Spring in a Place assigned; if the Thing be possible.

27. To bring a River from a Spring, or from another River, to a given Place, if the Thing be possible.

28. The Art of Levelling, or taking the Fall of Water, &c.

29. The great Rivers of a long Course enumerated.

30. Certain Rivers have Whirlpools and Swallows.

31. River-Water lighter than Sea-Water.

CHAP. XVII.

Of Mineral-Waters, Hot-Springs, &V. Page 359

1. No Water found pure and elementary.

2. Mineral Waters defined.

3. Three general Kinds of Mineral Waters.

4. To explain the Origin of Mineral Waters.

5. That the particular Species of Mineral Waters are infinite.

6. To enumerate the more remarkable and extraordinary Differences of Waters.

7. Of the Acidulæ, or tart Waters,

8. Of Hot Springs.

a a 9. Of 9. Of oily and unctuous Waters.

10. Of bitter Waters.

11. Of extreamly cold Springs.

12. Of such Waters as transmute or alter Substances.

13. Of poisonous and Mortal Waters.

14. Of coloured Waters.

15. Of Salt-Waters.

16. Of bubbling, or boiling, Springs, and such as break forth with a violent Spirit.

17. Springs that run only at stated Times.

CHAP. XVIII.

Of the Change, and Origin of dry Parts and watery, on the Earth. Page 395

1. To examine the extant Surface of the Earth, and that covered with Water.

2. T"be Surface of the Land and Water not perpetually the fame.

3. To compute how much Sand, and how much Water the Earth contains.

4. Waters forsake the Shores, and leave them dry on many Accounts j and first, as in Mears and Bogs.

5. Rivers forsake their Banks and Cbanels, and afford new Land.

6. Lakes are dried up, and changed to Land.

7. Streights are dried up. 8 Bays are dried up.

9. Parts of the Ocean are dried up.

10. To explain the Origin of Sand-Banks.

11. Whether Sand-Banks may become a part of the neighbouring Continent.

12. I/lands are formed several Ways.

13. The more extraordinary Ways wherein I/lands are formed.

14. Of Floating I/lands.

15. Rivers change their Chanels many Ways, or run over new Tracts of Land,

16. Lakes

16. Lakes, Meers, and Bogs possess Spaces of Land they did not occupy before.

17. The Ocean possesses new Trails of Land, where it did not appear before.

18. Whether the entire Surface of the Earth may be solely possessed by Water alone, or Land alone.

19. Why there are few Islands in the middle of the Ocean; but many Shoals of them near Continents, or larger Islands.

20. Why Lands prove fertile or barren i and why on the Sea-Shore the kind of Earth alters that covers the Fields.

CHAP. XIX.

Of the Air and Atmosphere. Page 419

1. Exhalations continually rife from the Parts of the Earth.

2. The State of the Atmosphere,

3. Exhalations are thicker or thinner at different Times, and in different Places.

4. Various Kinds of Exhalations.

5. The Particles of the Air rcflecl the Sun's Rays, like a Speculum.

6. The upper Parts of the Atmosphere are more rarified than the lower.

7. Exhalations are driven upwards by a violent Motion; tho' their natural Tendency is downwards.

f 8. The Atmosphere when warmed possesses a larger Space, and when cold a less. 9. To make a Thermometer, or Weather-Glass.

10. How, or to what Degree, the Air may be rarified.

11. Why the Air is generally thick and Cloudy in the Frigid Zone.

12. Why the Air is thin and clear in violently frosty Weather.

13. Why the Air appears thicker at the Horizon.

14. Whether the Air, or Atmosphere, be of the fame Height in all Places,

15. The

15. The Condensation and Rarifaction of the Air does not alter it's Height.

16. The Height of the Air the fame at all Times, and in all Places.

17. The Air more condensed in the Winter, and at Night, than in the Summer, and by Day.

18. The different Density of the Air in different Places.

19. The middle Region of the Air nearer the Earth in Places contiguous to the Pole.

20. In Places adjacent to the Pole the hot Region of the Air, or the beginning of the upper Region, is more remote.

21. The Rays of the Sun, Moon, and Stars are refracted in the Air.

22. On Account of this Refraction the Sun and Moon appear to rife sooner than they ought.

23. The thicker the Air, the greater the Refraction.

24. The thicker the Air, the sooner the Sun and Moon appear to rise.

25. The lower the Air that causes the Refraction, the sooner the Stars appear to rife.

26. The Refraction of a Star may be the fame in thefame Situation, tho' the Height of the Air be different.

27. If the Air be thicker, or lower, in one Place than in another, the Sun or Moon will appear sooner in the former than in the latter.

28. If the Air be thicker and higher in one Place than another, the Stars will accordingly be seen to rife sooner, or later.

29. Two Refractions being taken at two Altitudes, to find from thence both the Height and Thickness of the Air, with Respect to the Æther, or the Law of Refraction.

go. To find the least possible Height of the Atmosphere. 2i. To find the Law of Refraction.

32. To find the Refraction at any Inclination.

33. To find the Refraction at the given Height of a Star.

34. The Light of the Stars, particularly the Sun and Moont are reflected by the Particles of Air,

35. This 35. This Reflexion is the principal Cause of the Twilight.

36. When the Twilight begins.

37. The Height of the Air not to le found from the Quantity of the Twilight.

38. The Height of the Air, upon a Supposition that a double Reflection is the Cause of the Twilight.

39. The Height of the Air being givent to compute it's Quantity.

40. The Air has certain Peculiarities, in certain Places.

CHAP. XX.

Of the Motion of the Air, Winds in general, and the Points of the Compass. Page 477

1. Winds defined.

2.' Most Winds blow from one Point to the opposite.

3. Points of the Compass defined.

4. The Number of Points and Winds.

5. Two and thirty Points and Winds.

6. A more accurate Enumeration of the Points and Winds.

7. The Winds according to the Antients enumerated.

8. Another Enumeration of the Winds.

9. Opposite Winds.

10. Various Causes of Winds.

11. Why Winds may blow perpendicularly to the Horizon of a Place.

12. Why the Winds blow not in continued, but interrupted Blasts.

13. Why Winds very seldom blow perpendicularly upon a Place from above, but generally oblique.

14. Why the South and West Winds are warm.

15. Why the West Winds blow feldomer than the East.

16. Why the North and East Winds are stronger, and the South and West Winds weaker.

17. Why a small, thick, and blackish Cloud forelels Wind from that Quarter.

18. JVhy Winds arefrequent in the Spring and Autumn.

« AnteriorContinuar »