DIY History | Transcribe | Scholarship at Iowa | Eccentricity of the Sextant by Frederic Furbish, 1893 | Eccentricity of the Sextant by Frederic Furbish, 1893, Page 173

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Eccentricity of the Sextant by Frederic Furbish, 1893

Eccentricity of the Sextant by Frederic Furbish, 1893, Page 173

Reducing to angular measure x=0.72474x[2062648? or 4.8]" = 149488.351152 = 41degrees 31' 28.35.    Tan theta = y/z = -0.00095/+0.00393 = -0.24173 .   theta = 13degrees 35' 21[superscript]+[/superscript]" .   As the sign is -, the angle is in either the 2nd or 4th quadrant, either 166degrees 24' 39" or 346degrees 24' 39" .   [p? or c?]/[i? or l?] = square root of (y[superscript]2[/superscript]) + z[superscript]2[/superscript] = 0.004[superscript]+[/superscript]
With a six inch index arm this would be 0.024 inche which is entirely out of the question. x or y, the latitude is very accurately known to be 41degrees 40' +-10" , therefore the value found is certainly in error.
     As the entire work in the reduction of the circum-meridian altitude observations has been thoroughly checked, and as that in the foundation and reduction of the normal equations checks throughout, it may be said that a satisfactory result cannot be obtained from the series of observations presented. As the means of these series show a very small probable error, it is possible that the fault lies with sextant itself.
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Reducing to angular measure x=0.72474x[2062648? or 4.8]" = 149488.351152 = 41degrees 31' 28.35. Tan theta = y/z = -0.00095/+0.00393 = -0.24173 . theta = 13degrees 35' 21[superscript]+[/superscript]" . As the sign is -, the angle is in either the 2nd or 4th quadrant, either 166degrees 24' 39" or 346degrees 24' 39" . [p? or c?]/[i? or l?] = square root of (y[superscript]2[/superscript]) + z[superscript]2[/superscript] = 0.004[superscript]+[/superscript] With a six inch index arm this would be 0.024 inche which is entirely out of the question. x or y, the latitude is very accurately known to be 41degrees 40' +-10" , therefore the value found is certainly in error. As the entire work in the reduction of the circum-meridian altitude observations has been thoroughly checked, and as that in the foundation and reduction of the normal equations checks throughout, it may be said that a satisfactory result cannot be obtained from the series of observations presented. As the means of these series show a very small probable error, it is possible that the fault lies with sextant itself. [stamp circle at bottom left]