Part I. gives 



OF TWO PLACES BY MEANS OF THE BAROMETER. 



for H = 30.046 inches 



for h = 23.66 inches 



Difference 

 Part II. gives for T — T' = 7°.2, 



Approximate altitude a, 

 ±^{t-\-t' — 64) = 6.918 X 83.8, 



Second approximate altitude A, 

 Part III. gives for A = 6806, and L = 21° 

 Part IV. gives for 6806, 



Height above the sea, 



27649.7 

 21406.9 



6242.8 

 —16.9 



6225.9 

 +579.7 



6805.6 

 4-13.3 

 +19.3 



6838.2 feet. 



Example 2. 



M. Gay Lussac in his celebrated balloon ascent in 1805, found his barometer to 

 indicate 12.945 English inches, the temperature being 14°. 9 Fahrenheit. The ba- 

 rometer at Paris at the same time indicated 30.145 English inches with a tempera- 

 ture of 87°.44 Fahrenheit. Required the elevation of the balloon above Paris. 



^ for H = 30.145 inches, 27735.6 



Part 1. gives j ^^^ ^^, ^ ^^^^^ .^^^^^^ ^^^^ ^ 



Difference, 22085.2 



Part II. gives for T — T' = 72°.54, —169.9 



Approximate altitude a, 21915.3 



A (f ^ i^ _ 64) = 24.35 X 38.34, +933.6 



Second approximate altitude A, 22848.D 



Part III. gives for A = 22848, and L = 48° 50' —8.2 



Part IV. gives for 22848, +82.1 



Height of balloon above Paris, 22922.8 feet. 



51 



