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Astronomy explained upon Sir Isaac Newton's principles, and made easy to those who have not studied mathematics. To which are added, a plain method of finding the distances of all the planets from the sun, by the transit of venus over the sun's disc, in the year 1761 ... / by James Ferguson
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8 9

Hydroßatical Talks.

6 Inches diameter.

6~ Inches diameter.

Ti

n>

Solidity

Weight 1

In avoir-

rt>

Solidity

Weight

In avoir-

in eubic

in troy

dupoiie

s

in eubie

in troy

dupoiie

er

qjT

inches.

ounces.

ounces.

tr

CXQ*

er

inches.

ounces

ounces.

i

339-3

179.0

196.6

I

398.2

210.1

230.7

2

678.6

358.1

393-3

2

797-4

420.3

461.4

3

1017.9

537-2

589.9

3

1195.6

630.4

692.1

4

i357- 2

7x6.2

786.5

4

1593-8

840.6

922.8

5

j 696.5

895-3

983.1

5

199 x, 9

1050.8

1153-6

6

2035.7

1074.3

1179.8

6

2390.1

1260.9

1384.3

7

2375-0

1253.4

1376-4

7

2788.3

1471-1

1615.0

8

27 1 4 * 3

1432 4

1573-0

8

3186.5

1681.2

1845.7

9

3053.6

1611.5

1769.6

9

3584.7

1891.3

2076.4

IO

3392.9

1790.6

1966.3

10

3982.9

2lOl-5

2307.1

20

6785.8

358 i.i

3932.5

20

7965.8

4202.9

4614.3

3°

10178.8

537 l -7

5898.8

30

11948.8

6304.4

6921.4

40

13571.7

7162.2

7865.1

40

i593l-7

8405.9

9228.6

5°

16964.6

8952.8

9831.4

50

19914.6

10507.4

11535-7

60

20357.5

10743-3

11 797.6

60

23897.6

12608.9

13842.9

70

23750.5

12 533-9

13763.9

70

27880.5

14710.4

16150.0

80

2 743-4

14324-4

15730.2

80

31863.4

168 1 1.8

18457-2

90

30536.3

16x15.0

17696.5

9°

35846.3

18913.3

20764.3

100

33929.2

17905.6

19662.7

100

39829.3

21014.8

23071.5

200

67858.4

35811.2

39325-4

200

79658.6

42029.6

46143-0

6. Whenever a vacuum, is made in any vessel, the air by its weightwill endeavour to rush into the vessel, or to drive in any other bodythat will give way to its pressure ; as may be easily seen by a commonsyringe. For, if you stop the bottom of a syringe, and then draw upthe piston, if it be so tight as to drive out all the air before it, andleave a vacuum within the syringe, the piston being let go will bedriven down with a great force.

7- The force with which the piston is drove down, when there is avacuum under it, will be as the square of the diameter of the bore inthe syringe. That is to say, it will be driven down with four timesas much force in a iyringe of a two-inch bore, as in a syringe of oneinch : for the areas of circles are always as the squares of their dia-meters.

N

8. The