+----------------------------------------------------+ | Height in |Correction|| Height in |Correction| |Thousand Feet.| Additive.||Thousand Feet.| Additive.| |--------------+----------++--------------+----------| | 1 | 3 || 14 | 44 | | 2 | 5 || 15 | 48 | | 3 | 8 || 16 | 52 | | 4 | 11 || 17 | 56 | | 5 | 14 || 18 | 60 | | 6 | 17 || 19 | 65 | | 7 | 20 || 20 | 69 | | 8 | 23 || 21 | 74 | | 9 | 26 || 22 | 78 | | 10 | 30 || 23 | 83 | | 11 | 33 || 24 | 88 | | 12 | 37 || 25 | 93 | | 13 | 41 || 26 | 98 | +----------------------------------------------------+ EXAMPLE 1. On October 21st, 1852, when Mr. Welsh ascended in a balloon, at 3h. 30m. p.m., the barometer, corrected and reduced, was 18.85, the air temperature 27 deg., while at Greenwich, 159 feet above the sea, the barometer at the same time was 29.97 inches, air temperature 49 deg., the balloon not being more than 5 miles S.W. from over Greenwich; required its elevation. Feet. Barometer in Balloon 18.85, Table I. = 13007 " at Greenwich 29.97 " 883 ----- 12124 Mean Temperature, 38 deg., Table II. Factor 1.012 ----- 12269. ----- Latitude 51-1/2 deg., Factor from Table III. .99941 ----- 12262 Correction from Table IV. 38 ----- 12300 Elevation of Greenwich 159 ----- " Balloon 12459 feet. ===== The following examples, from the balloon ascents of J. Glashier, Esq., F.R.S., will serve for practice.[4] 2. Ascended from Wolverhampton, 18th August, 1862, at 2h. 38m. p.m.; barometer (in all cases corrected and reduced to 32 deg. F) was 14.868, the temperature of the air 26 deg.; at the same time, at Wrottesley Hall, 531 feet above the sea, in latitude 52-1/2 deg. N, the barometer was 29.46, and the temperature of the air 65 deg.4; find the elevation of the balloon above the sea. Height, 18,959 feet.