70 PHYSICS OF THE AIR
TABLE II.—PERCENTAGE DISTKIBUTION OF GASES IN THE ATMOSPHERE
Gases
Height in kilo** Total
meters Argon Nitrogen Water vapor Oxygen Carbon dioxide Hydro-. gen Helium pressui"e in. milli-
meters
140 0.01 99.15 0.84 0 . OO4O
130 0.04 99.00 0.96 0 . OO4<3
120 0.19 • 98.74 1 .07 O.OO52
110 0.67 0.02 0.02 98.10 1.19 0 . OO5O
100 2.95 0.05 0.11 95.58 1.31 O.OO67
90 9.78 0.10 0.49 88.28 1.35 o.oosi
80 32.18 0.17 1.85 64.70 1.10 0.0123
70 0.03 61.83 0.20 4.72 32.61 0.61 0.0274
60 0.03 81.22 0.15 7.69 10.68 0.23 O.O93-5
50 0.12 86.78 0.10 10.17 2.76 0.07 0.403
40 0.22 86.42 0.06 12.61 0.67 0.02 1.84
30 0.35 84.26 0.03 15.18 0.01 0.16 0.01 8.63
20 0.59 81.24 0.02 18.10 0.01 0.04 40.99
15 0.77 79.52 0.01 19.66 0.02 0.02 89.66
11 0.94 78.02 0.01 20.99 0.03 0.01 168. OO
5 0.94 77.89 0.18 20.95 0.03 0.01 405
0 0.93 77.14 1.20 20.69 0.03 0.01 760
1. That at the surface of the earth the principal gases of the atmosphere and their respective volume percentages in dry air are:
Nitrogen....................... 78.08
Oxygen........................ 20.94
Argon......................... 0.94
Hydrogen...................... 0.01
Neon......................... O.OO12
Helium........................ O.OOO4:
Carbon dioxide................ 0.03
2. That at the surface of the earth water vapor supplies 1.2 per cent of the total number of gas molecules present.
3. That the absolute humidity rapidly decreases, under the influence of lower temperatures, with increase of height, to a negligible amount at or below the level of 10 kilometers.
4. That the temperature decreases normally, as per average of many observations, from 11° C. at sea level to —55° C. at an elevation of 11 kilometers.
5. That beyond 11 kilometers above sea level the temperature remains constant at —55° C.
6. That up to the level of 11 kilometers the relative percentages of the several gases, excepting water vapor, remain constant—a result, of course, of vertical convection.