Terrestrial Refraction. 559 



Table V. (Dips.) 



O . D r D 2 . D 3 . D r 



90° 0° 49' 52" 1° 14' 26" 1° 33' 5" 1° 48' 48" 



89 30' 1 1 20 1 22 32 1 39 39 1 54 28 



89 1 21 12 1 38 19 1 53 6 2 6 20 



88 2 12 9 2 23 25 2 34 2 44 



87 3 8 22 3 16 28 3 24 20 3 32 



86 4 6 21 4 12 36 4 18 46 4 24 52 



85 5 5 6 5 10 10 5 15 13 5 20 14 



83 7 3 41 7 7 22 7 11 3 7 14 45 



80 10 2 34 10 5 9 10 7 46 10 10 22 



75 15 1 41 15 3 23 15 5 5 15 6 48 



70 20 1 14 20 2 29 20 3 45 20 5 2 



60 30 47 30 1 34 30 2 22 30 3 10 



50 40 33 40 1 6 40 1 39 40 2 13 



40 50 22 50 45 50 18 50 1 33 



20 70 10 70 20 70 30 70 40 



90 90 90 90 



0o- D, 5 . D G . D 7 . IV 



90° 2° 2' 41" 2° 15' 17" 2° 26' 56" 2° 37' 50" 



89 30' 2 7 43 2 19 51 2 31 8 2 41 44 



89 2 18 27 2 29 43 2 40 19 2 50 22 



88 2 53 31 3 2 38 3 11 25 3 19 54 



87 3 39 28 3 46 45 3 53 53 4 52 



86 4 30 53 4 36 49 4 42 42 4 48 30 



85 5 25 14 5 30 11 5 35 7 5 40 1 



83 7 18 27 7 22 9 7 25 51 7 29 34 



80 10 12 59 10 15 38 10 18 17 10 20 57 



75 15 8 33 15 10 19 15 12 7 15 13 56 



70 20 6 19 20 7 37 20 8 55 20 10 14 



60 30 3 59 30 4 48 30 5 38 30 6 28 



50 40 2 47 40 3 21 40 3 56 40 4 31 



40 50 1 57 50 2 21 50 2 45 50 3 9 



20 70 50 70 1 1 70 1 12 70 1 23 



90 90 90 90 



6*. Refraction Correction for Instruments. 



The values of A<£; given in Table II., and calculated by 

 means of (2b), give the total turning of the ray of light 

 ( wave-length 5000 A. U.) when it proceeds from a height zero 

 (sea-level) to a height /*,km. Accordingly, the values of A</>; 



