DIY History | Transcribe | Scholarship at Iowa | Eccentricity of the Sextant by Frederic Furbish, 1893 | Eccentricity of the Sextant by Frederic Furbish, 1893, Page 103

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Eccentricity of the Sextant by Frederic Furbish, 1893

Eccentricity of the Sextant by Frederic Furbish, 1893, Page 103

[page][illegible][/page]

33.5° F and the barometer reading 29.2 in. By interpolation in table IIA we find the mean refraction for 37 3/4° = 75.2". In table IIB the factor for 29.2 in is 0.973. In table IID the factor for a detached thermometer reading of 33.5° is 1.033. Multiplying, 75.2" x 0.973 x 1.033 = 75.58" which is recorded in column (b). C = ((Π/2) + δ + b) - (1/2) ∝' or here 
   89° 59' 60" 
-  10   36  23.1
---------------------
   79° 23' 36.9"
            1   15.54
----------------------
    79° 24'  52.49"
    37   44   41.53
----------------------
    41°  40'  10.96"

This is recorded in the column headed C.

In the column headed C' write C in circular measure. This is accomplished by dividing 41° 40' 10.96" (expressed in seconds) by 206264.8 giving 0.7272737. The work is done most conveniently of course by logarithms. 

The next step is to form a series of equations of the form x + Ay + Bz = C.

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[page][illegible][/page] 33.5° F and the barometer reading 29.2 in. By interpolation in table IIA we find the mean refraction for 37 3/4° = 75.2". In table IIB the factor for 29.2 in is 0.973. In table IID the factor for a detached thermometer reading of 33.5° is 1.033. Multiplying, 75.2" x 0.973 x 1.033 = 75.58" which is recorded in column (b). C = ((Π/2) + δ + b) - (1/2) ∝' or here 89° 59' 60" - 10 36 23.1 --------------------- 79° 23' 36.9" 1 15.54 ---------------------- 79° 24' 52.49" 37 44 41.53 ---------------------- 41° 40' 10.96" This is recorded in the column headed C. In the column headed C' write C in circular measure. This is accomplished by dividing 41° 40' 10.96" (expressed in seconds) by 206264.8 giving 0.7272737. The work is done most conveniently of course by logarithms. The next step is to form a series of equations of the form x + Ay + Bz = C.