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18. 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 Rise of Springs. 24. To find whether a Spring, or Well, may be

made in a Place asigned. 25. To make a well in a given Spot; if the

Thing be possible. 26. To make an apparent Spring is a Place

asigned ; 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 Wa

ter, &c. 29. The great Rivers of a long Course enumerated. 30. Certain Rivers bave Whirlpools and Swallows, 31. River-Water lighter than Sea-Water,

CH A P. XVII.

Of Mineral-Waters, Hot-Springs, &c. 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 extra.

ordinary Differences of Waters. 7. Of thé Acidulæ, or tart Waters, 8. Of Hot Springs.

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9. Of

9. Of oily and unetuous 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.

CHA P. 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. The Surface of the Land and Water not perpe

tually the same. 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; and first, as in Mears and Bogs. 5. Rivers for sake their Banks and Chanels, and af

ford 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. Isands are formed several Ways. 13. The more extraordinary Ways wherein Islands are

formed. 14. Of Floating Islands. 15. Rivers change their Chanels many ways, or run over ner Traets of Land.

16. Lakes

16. Lakes, Meers, and Bogs possess Spaces of Land

they did not occupy before. 17. The Ocean poseljes new Traets of Land, where it

did not appear before. 18. Whether the entire Surface of the Earth may be

folely polesed by Water alone, or Land alone. 19. Why ibere are few Isands in the middle of the

Ocean ; but many Shoals of them near Continents,

or larger Isands. 20. Wby Lands prove fertile or barren; and why on

the Sea-Shore the kind of Earth alters that covers the Fields.

CH A P. XIX.

Of the Air and Atmosphere. Page 419 1. Exhalations continually rise 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 refleet 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 Mon

tion ; tho' their natural Tendency is downwards. 8. The Atmosphere when warmed poseljes a larger

Space, and when cold a lefs. 9. To make a Thermometer, or Weather-Glass. 10. How, or to what Degree, the Air may be rarified. II, Wby 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

8. The tbo their naturen upwards by an

15. The Condensation and Rarifačtion of the Air

does not alter it's Height. 16. The Height of the Air the same 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 re

fracted in the Air. 22. On Account of this Refraction the Sun and Moon

appear to rise 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 rise. 26. The Refra&tion of a Star may be the same in the same

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 bigher in one place than

another, the Stars will accordingly be seen to rise

sooner, or later. 29. Two Refractions being taken at two Altitudes, to

find from thence both the Height and Thickness of ibe Air, with Respect to the Æther, or the

Law of Refraction. 30. To find the least possible Height of the Atmosphere. 31. To find the Law of Refra&tion. 32. To find the Refraction at any Inclination. 33. To find the Refra&tion at the given Height of a Star. 34. The Light of the Stars, particularly the Sun and

Moon, are reflected by the Particles of Air.

35. This 35. This Refle&tion is the principal Cause of the Twilight. 36. Wben tbe Twilight begins. 37. The Height of the Air not to be found from the

Quantity of the Twilight. 38. Tbe Height of the Air, upon a Supposition that

a double Reflection is the cause of the Twilight. 39. The Height of the Air being given, to compute

it's Quantity. 40. The Air bas certain Peculiarities, in certain Places.

CHA P. XX.

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

Page 477 1. Winds defined. 2: Moft Winds blow from one point to the opposite. 3. Points of the Compass defined. 4. The Number of Points and Winds,

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. II. Wby Winds may blow perpendicularly to the Ho

rizon of a Place. 12. Wby the Winds blow not in continued, but inter

rupted Blasts. 13. Wby Winds very seldom blow perpendicularly upon

a Place from above, but generally oblique. 14. Wby the South and West Winds are warm. 15. Wby the West Winds blow seldomer than the East. 16. Wby the North and East Winds are stronger, and

the South and West Winds weaker. 17. Why a small, thick, and blackish Cloud foretels

Wind from that Quarter. 18. Wby Winds are frequent in the Spring and Autumn.

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