Double 1000 Yards, the Height from the Earth to the Clouds for an Addition to the Diameter of the Earth, whose Surface is now considered, as extended to the concentric Floor of Cloud.

1000
1000
——
2000

SECOND.

13932702(1⁄3)

Diameter of the Earth in Yards.

2000

Addition to the Diameter.

————

13934702

Sum, to which add

1332

the Height of the Eye or of the

————

Balloon above the Floor of Cloud.

13936034

Sum, which multiply into

1332

the Height of the Eye above the

————

Floor.

27872068

41808102

41808102

13936034

——————

Extract the

. . . . .

1760) Yards in a Mile.
Square Root

18562797288

(136245 (77 Miles.

1

12320

———

23) 85

13045

69

12320

——

———

266) 1662

Yards 440) 725

(1 Quarter of a Mile.

1596

440

——

——

2722) 6679

285

Yards.

5444

———

Ans. 77

Miles, 1 Qu. 285 Yards.

27244) 123572

108976

———

272485) 1459688

1362425

————

97263

Circular Boundary of the terrestrial Prospect from the Balloon on a clear Day.

PROBLEM.

To find the circular Boundary of the terrestrial Prospect, on a clear Day, from the Balloon at the Height of near a Mile and half, viz. 2332 Yards: the Earth’s Diameter being

equal to13932705⁠2⁄3Yards,
add 2332the Height of the Eye or Balloon.
————
13935037he Sum, multiply into
2332the Height of the Eye, &c.
————
27870074
41805111
41805111
27870074
——————
Extract the. . . . . 1760) Yards in a Mile.
square Root32496506284(180267(102,
11760 say 102​1⁄2 Miles, Ans.
——
28)2244267
2243520
————
3602) 9650747 Yards, Remainder.
7204
———
36046) 244662
216276
————
360527) 2838684
2523689
————
314995Remainder.

[19] See his “Minute Philosopher.”

[20] Ullòa in his voyage to South-America relates, that in passing over the Deserts, Írides are frequently seen by Travellers round their own Heads as the Center of the Iris; and visible only to themselves. But what Analogy the Balloon Iris bears to them, Time and future Experiments may discover. See his “Voyage to South America, Vol. 1. Pa. 442.”