Airopaidia : $b Containing the narrative of a balloon excursion from Chester, the eighth of September, 1785, taken from minutes made during the voyage; hints on the improvement of balloons ... To which is subjoined, mensuration of heights by the barometer, made plain; with extensive tables. The whole serving as an introduction to aërial navigation.Baldwin, Thomas
History
Airopaidia : $b Containing the narrative of a balloon excursion from Chester, the eighth of September, 1785, taken from minutes made during the voyage; hints on the improvement of balloons ... To which is subjoined, mensuration of heights by the barometer, made plain; with extensive tables. The whole serving as an introduction to aërial navigation.
Baldwin, Thomas
Aeronautics -- Early works to 1900; Balloons -- Early works to 1800
Reducing then the Numbers 66 and 72, to the lowest Denomination, thus
6)⁶⁶⁄₇₂ = ¹¹⁄₁₂ the Proportion which the _Length_ of the _Shadow_ bears
to the _Height_ of the _Object_ is thereby obtained: that is
[26] If the _Length_ of the Shadow be divided into 12 Parts, the Height
of the Object would be 11 of those Parts.
See Moore’s Practical Navigator. See Page 98 [34].
PROBLEM.
An +easy+ Way to find the Proportion which the _Length_ of the Shadow
bears to the _Height_ of an Object is, +AT ANY TIME WHEN THE SUN
SHINES+, to fix a Plummet Line and +frame+ _upright_ in the Ground;
measure the _Length_ of its _Shadow_, and compare _it_ with the
_Height_ of the +frame+.
[27] Equal to 3 Quarters of a Mile and 121 Yards.
[28] i.e. When the Barometer _below_ is at 30 Inches, and Thermometer
_below_ at 60° viz. about 1000 Yards high in _fine_ Weather, and 500 in
_changeable_.
[29] Being 1083 Yards, i.e. half a Mile, and 203 Yards.
[30] It was High Water at Chester and Frodsham-Bridge, at 38 Minutes
past I.
[31] Articles parted with, to check the _first_ Descent at Bellair,
near Frodsham: and to ascend the _second_ Time.
To check the _first_ Descent. Pounds. Ounces.
Ballast, at twice: 24 0
To clear Trees and Hedges, and
_re-ascend_:
Barometer and Frame, 0 12½
Basket with Tunning Dish and
Bottles (except the Flask with
Brandy and Water) 4 10
Half Mile of Twine on the Reel 1 0
Speaking Trumpet 0 8½
Woollen Gloves 0 1
———————
31 0
24 0
———————
Remains for Re-ascent 7 0
[32] The Sun’s Azimuth from the North Point _Westward_, being 118.26′:
its Supplement to 180° is 61°.34′ South westerly: i.e. South West by
West, half West _nearly_.
[33] The _Length_ of the Shadows being more than _double_ the Height of
the +Objects+: see [34].
[34] To find the Length of the Shadow at half past III. (See Section
84, Note _a_.)
{Lat. of Chester, 53° 12′}
Given {Sun’s Dec. 5 29 } To find Sun’s Alt.
{Hour III, 30M. 52 30 }
This is the Case of an oblique spheric Triangle, wherein are two Sides
and one Angle between them given, to find the Sun’s Azimuth, and the
Sun’s Co-Alt.
Side 84. 31 } Sum of Sides 121. 19
Side 36. 48 } Diff. of Sides 47. 43
(3½ Hour) Angle contained 52. 30
Half ditto 26. 15 } 63. 45
Half Sum of Sides 60. 39 } Co. 29. 22
Half Difference ditto 23. 51 } 66. 9
THE FIRST PREPARATIVE PROPORTION.
Public-domain text, read in full here on John Shaqi.
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