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Airopaidia

Chapter 134: The use.
By Thomas Baldwin
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About This Book

The work presents a first-person account of an 18th-century balloon voyage launched from a regional town, pairing vivid descriptions of aerial scenes with practical instruction. The narrative records observations made during ascent and flight and is accompanied by engraved views; it also offers proposals for balloon design and a method of inflation by steam, precautions against descent over water, and inquiries into atmospheric conditions affecting direction. A clear, practical explanation of measuring height with the barometer is included, together with extensive tables. The material functions as an introduction to aërostatic navigation that mixes travel narrative, natural-philosophical observation, and engineering advice.

CHAPTER  LXXIII.

USE AND PRACTICE OF THE SECOND TABLE IN THE FIRST EXAMPLE.

The use.

Section 369. TO find the Heights, in Feet and Tenths, in the Atmosphere, corresponding to the Points at which the Quicksilver stands in both Barometers, which have now the same Temperature, viz. that of the warmer Barometer, on a Supposition that they were both exposed to the Standard-Temperature of 31°.24, on Farenheit’s Scale.

The practice.
The 7th Step applied in the first Example.

370. Look at the first Column, in the second Table, for

25.2, and the Answer is 6225.0 in the second Column; and for

29.4, and the Answer is 2208.2. The Answers are the Heights, in Feet and Tenths, in the Atmosphere, at which the Quicksilver stands in both Barometers, with the Temperature of 31°.24: corresponding to their respective Points, for which sole Purpose this Table is calculated.

371. 8th Step. Having placed the Barometers and their corresponding Heights in the Atmosphere, shewn by the second Table, at one View: subtract the lesser from the whole Height, and there will remain, secondly; (see Section 367) the greater Height, viz. the Height corresponding to the Barometer in the elevated Station, above the Height corresponding to the Barometer, on the Ground, (both being at the Temperature of 31°.24) thus:

Feet.
Inches 25.2 correspond to 6225.0
Inches 29.4 correspond to 2208.2; subtract:
———
and the Remainder is
 4016.8

viz. a Number in Feet and Tenths corresponding to the Height of the upper above the lower Barometer, both being in the Temperature of 31°.34.

THE SECOND TABLE.

The 1st Column shews the Quicksilver in the barometric Tube standing at each Inch from 1 to 10, and at each Tenth from 10 to 32 Inches.

The 2d Column shews the Height of the barometric Tube, above the imaginary Level at 32 Inches,—with the Temperature of 31.24;—in Feet and Tenths, answering to Inches and Tenths of the Barometer in the first Column.

The 3d Column shews the Height in Feet and Tenths, answering to a Tenth of an Inch on the Barometer, being the difference between each two adjoining Heights in the 2d Column.

Inch. Feet. Differ-
ence.		 Inch. Feet. Diff. Inch. Feet. Diff.
1   
90309.0
18061.8
16.8
16790.4
154.6
24.5
6959.0
106.1
2   
72247.2
10565.4
.9
16635.8
153.7
.6
6852.9
105.7
3   
61681.8
7496.4
17.0
16482.1
152.9
.7
6747.2
105.3
4   
54185.4
5814.6
.1
16329.2
151.9
.8
6641.9
104.9
5   
48370.8
4750.9
.2
16177.3
151.1
.9
6537.0
104.4
6   
43619.9
4016.8
.3
16026.2
150.2
25.0
6432.6
104.0
7   
39603.1
3479.5
.4
15876.0
149.3
.1
6328.6
103.6
8   
36123.6
3069.2
.5
15726.7
148.5
.2
6225.0
103.2
9   
33054.4
2745.4
.6
15578.2
147.6
.3
6121.8
102.8
10.0
30309.0
259.6
.7
15430.6
146.8
.4
6019.0
102.4
.1
30049.4
256.4
.8
15283.8
146.0
.5
5916.6
102.0
.2
29793.0
254.3
.9
15137.8
145.2
.6
5814.6
101.6
.3
29538.7
251.8
18.0
14992.6
144.3
.7
5713.0
101.2
.4
29286.9
249.3
.1
14848.3
143.6
.8
5611.8
100.8
.5
29037.6
247.0
.2
14704.7
142.8
.9
5511.0
100.6
.6
28790.6
244.7
.3
14561.9
142.0
26.0
5410.4
99.8
.7
28545.9
242.4
.4
14419.9
141.2
.1
5310.6
99.7
.8
28303.5
240.2
.5
14278.7
140.5
.2
5210.9
99.3
.9
28063.3
237.9
.6
14138.2
139.7
.3
5111.6
98.8
11.0
27825.4
235.8
.7
13998.5
139.0
.4
5012.8
98.6
.1
27589.6
233.7
.8
13859.5
138.2
.5
4914.2
98.1
.2
27355.9
231.6
.9
13721.3
137.5
.6
4816.1
97.8
.3
27124.3
229.6
19.0
13583.8
136.8
.7
4718.3
97.4
.4
26894.7
227.6
.1
13447.0
136.1
.8
4620.9
97.0
.5
26667.1
225.6
.2
13310.9
135.3
.9
4523.9
96.7
.6
26441.5
223.7
.3
13175.6
134.5
27.0
4427.2
96.4
.7
26217.8
221.7
.4
13041.1
134.2
.1
4330.8
95.9
.8
25996.1
220.0
.5
12906.9
133.3
.2
4234.9
95.7
.9
25776.1
218.0
.6
12773.6
132.6
.3
4139.2
95.2
12.0
25558.1
216.3
.7
12641.0
131.9
.4
4044.0
95.0
.1
25341.8
214.4
.8
12509.1
131.3
.5
3949.0
94.5
.2
25127.4
212.7
.9
12377.8
130.6
.6
3854.5
94.3
.3
24914.7
211.0
20.0
12247.2
130.0
.7
3760.2
93.9
.4
24703.7
209.3
.1
12117.2
129.3
.8
3666.3
93.6
.5
24494.4
207.7
.2
11987.9
128.7
.9
3572.7
93.2
.6
24286.7
206.0
.3
11859.2
128.0
28.0
3479.5
92.9
.7
24080.7
204.3
.4
11731.2
127.4
.1
3386.6
92.6
.8
23876.4
202.8
.5
11603.8
126.8
.2
3294.0
92.2
.9
23673.6
201.2
.6
11477.0
126.2
.3
3201.8
91.9
13.0
23472.4
199.7
.7
11350.8
125.6
.4
3109.9
91.6
.1
23272.7
198.2
.8
11225.2
125.0
.5
3018.3
91.3
.2
23074.5
196.6
.9
11100.2
124.4
.6
2927.0
90.9
.3
22877.9
195.2
21.0
10975.8
123.7
.7
2836.1
90.7
.4
22682.7
193.7
.1
10852.1
123.3
.8
2745.4
90.3
.5
22489.0
192.4
.2
10728.8
122.6
.9
2655.1
90.0
.6
22296.6
191.0
.3
10606.2
122.0
29.0
2565.1
89.7
.7
22105.6
189.4
.4
10484.2
121.5
.1
2475.4
89.4
.8
21916.2
188.1
.5
10362.7
120.9
.2
2386.0
89.1
.9
21728.1
186.8
.6
10241.8
120.4
.3
2296.9
88.7
14.0
21541.3
185.5
.7
10121.4
119.8
.4
2208.2
88.5
.1
21355.8
184.1
.8
10001.6
119.2
.5
2119.7
88.2
.2
21171.7
182.9
.9
9882.4
118.8
.6
2031.5
87.9
.3
20988.8
181.6
22.0
9763.6
118.1
.7
1943.6
87.6
.4
20807.2
180.3
.1
9645.5
117.7
.8
1856.0
87.3
.5
20626.9
179.0
.2
9527.8
117.1
.9
1768.7
87.0
.6
20447.9
178.0
.3
9410.7
116.6
30.0
1681.7
86.7
.7
20269.9
176.7
.4
9294.1
116.0
.1
1595.0
86.4
.8
20093.2
175.4
.5
9178.1
115.6
.2
1508.6
86.2
.9
19917.8
174.3
.6
9062.5
115.1
.3
1422.4
85.8
15.0
19743.5
173.1
.7
8947.4
114.5
.4
1236.6
85.6
.1
19570.4
172.0
.8
8832.9
114.0
.5
1251.0
85.3
.2
19398.4
170.9
.9
8718.9
113.6
.6
1165.7
85.0
.3
19227.5
169.8
23.0
8605.3
113.0
.7
1080.7
84.7
.4
19057.7
168.6
.1
8492.3
112.6
.8
996.0
84.5
.5
18889.1
167.6
.2
8379.7
112.1
.9
911.5
84.2
.6
18721.5
166.5
.3
8267.6
111.6
31.0
827.3
83.9
.7
18555.0
165.4
.4
8156.0
111.1
.1
743.4
83.7
.8
18389.6
164.1
.5
8044.9
110.6
.2
659.7
83.4
.9
18225.5
163.7
.6
7934.3
110.2
.3
576.3
83.1
16.0
18061.8
162.4
.7
7824.1
109.7
.4
493.2
82.8
.1
17899.4
161.3
.8
7714.4
109.3
31.5
410.4
82.6
.2
17738.1
160.4
.9
7605.1
108.8
.6
327.8
82.4
.3
17577.7
159.3
24.0
7496.3
108.3
.7
245.4
82.0
.4
17418.4
158.4
.1
7388.0
107.9
.8
163.4
81.8
.5
17260.0
157.5
.2
7280.1
107.5
.9
81.6
81.6
.6
17102.5
156.5
.3
7172.6
107.0
32.0
00.0
.7
16946.0
155.6
.4
7065.6
106.6

372. Now apply the third Table, or Table for Tenths, if necessary; including two more Steps, viz. the 9th and 10th: which, being useless, in the first Example, are, for the present, omitted.

373. An Explanation of the third Table, or Table for Tenths, is, however, for the Sake of Order, here subjoined.⁠[122]

THE THIRD TABLE, OR TABLE FOR TENTHS:

Serving to compleat the 2d Table, on Expansion of the Barometer, with the Temperature of 31°.24.

1. The upper horizontal Figures shew the Number of Parts into which the Tenth of an Inch has been divided.

2. The Figures in the left vertical Column express the Height in feet, (above the imaginary Level, at 32 Inches of the Barometer,) or Expansion corresponding to a single Tenth of an Inch of Quicksilver.

3. The feet in the Place of Meeting are called tenths: thus, 90 Feet are 9 Tenths of 100 Feet.

Feet. Parts into which the Tenth of an Inch is divided.
1⁄10 2⁄10 3⁄10 4⁄10 5⁄10 6⁄10 7⁄10 8⁄10 9⁄10
81
8
16
24
32
40
49
57
65
73
82
8
16
25
33
41
49
57
66
74
83
8
17
25
33
41
50
58
66
75
84
8
17
25
34
42
50
59
67
76
85
8
17
25
34
42
51
59
68
76
86
9
17
26
34
43
52
60
69
77
87
9
17
26
35
43
52
61
70
78
88
9
18
26
35
44
53
62
70
79
89
9
18
27
36
44
53
62
71
80
90
9
18
27
36
45
54
63
72
81
91
9
18
27
36
45
55
64
73
82
92
9
18
28
37
46
55
64
74
83
93
9
19
28
37
46
56
65
74
84
94
9
19
28
38
47
56
66
75
85
95
9
19
28
38
47
57
66
76
85
96
10
19
29
38
48
58
67
77
86
97
10
19
29
39
48
58
68
78
87
98
10
20
29
39
49
59
69
78
88
99
10
20
30
40
49
59
69
79
89
100
10
20
30
40
50
60
70
80
90
101
10
20
30
40
50
61
71
81
91
102
10
20
31
41
51
61
71
82
92
103
10
21
31
41
51
62
72
82
93
104
10
21
31
42
52
62
73
83
94
105
10
21
31
42
52
63
73
84
94
106
11
21
32
42
53
64
74
85
95
107
11
21
32
43
53
64
75
86
96
108
11
22
32
43
54
65
76
86
97
109
11
22
33
44
54
65
76
87
98
110
11
22
33
44
55
66
77
88
99
111
11
22
33
44
55
67
78
89
100
112
11
22
34
45
56
67
78
90
101
113
11
23
34
45
56
68
79
90
102
114
11
23
34
46
57
68
80
91
103
115
11
23
34
46
57
69
80
92
103
116
12
23
35
46
58
70
81
93
104
117
12
23
35
47
58
70
82
94
105
118
12
24
35
47
59
71
83
94
106
119
12
24
36
48
59
71
83
95
107
120
12
24
36
48
60
72
84
96
108
121
12
24
36
48
60
73
85
97
109
122
12
24
37
49
61
73
85
98
110
123
12
25
37
49
61
74
86
98
111
124
12
25
37
50
62
74
87
99
112
125
12
25
37
50
62
75
87
100
112
126
13
25
38
50
63
76
88
101
113
127
13
25
38
51
63
76
89
102
114
128
13
26
38
51
64
77
90
102
113
129
13
26
39
52
64
77
90
103
116
130
13
26
39
52
65
78
91
104
117