OF TWO PLACES BY MEANS OF THE BAROMETER. 



( for H = 30.046 inches 27649.7 



J (for h = 23.66 inches 21406.9 



Difference 6242.8 



Part II. gives for T T' = 7.2, 16.9 



Approximate altitude a, 6225.9 



- ( t + t i 64) = 6.918 x 83.8, +579.7 



Second approximate altitude A, 6805.6 



Part III. gives for A = 6806, and L = 21, +13.3 



Part IV. gives for 6806, +193 



Height above the sea, 6838.2 feet. 



Example 2. 



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

 icate 12.945 English inches, the temperature being 14.9 Fahrenheit. The ba- 

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

 of 87.44 Fahrenheit. Required the elevation of the balloon above Paris. 



Part I. gives 



for H = 30.145 inches, 

 for h' = 12.945 inches, 



Difference, 

 Part II. gives for T T' = 72.54, 



Approximate altitude a, 

 ^L(t + t' 64) = 24.35 x 38.34, 



27735.6 

 5650.4 



22085.2 

 169.9 



21915.3 

 +933.6 



Second approximate altitude A, 22848.9 



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 



