DIY History | Transcribe | Scholarship at Iowa | Eccentricity of the Sextant by Frederic Furbish, 1893 | Eccentricity of the Sextant by Frederic Furbish, 1893, Page 46

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Eccentricity of the Sextant by Frederic Furbish, 1893

Eccentricity of the Sextant by Frederic Furbish, 1893, Page 46

the line D thus 30, 40, 50 etc. Each 5th degree is marked with a small [[diamond-shaped mark]] just above the line A. [[drawing of scale similar to the following...]]
D 60                                D
________________________
A                                v   A
________________________
     |     |     |     |     |     |   
B   |  |  |  |  |  |  |  |  |  |  |   B
________________________
     |||||||||||||||||||||||||||||||   
C   |||||||||||||||||||||||||||||||   C
________________________

The degrees are marked by vertical lines running from C to A and are not numbered in any way. The half degrees are marked by vertical lines running from C to a point half way between A and B. The 10' marks are vertical lines running from C to B.

     The Vernier is marked thus: - The minute lines run from A to C, the half minute (30") lines from C to a point half way between B and A, and the 10" lines from B to C. [[drawing of Vernier scale similar to the following...]]
C________________C
     |||||||||||||||||||||||||  
     |||||||||||||||||||||||||   
B________________B
     |  |  |  |  |  |  |  |  | 
     |     |     |     |     |    
A________________A
     ^          2          4
The 0 is marked with a [[diamond-shaped mark]] below A and the even minutes up to 10 are marked 2, 4, 6 etc. below A. The odd minutes are not numbered.

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the line D thus 30, 40, 50 etc. Each 5th degree is marked with a small [[diamond-shaped mark]] just above the line A. [[drawing of scale similar to the following...]] D 60 D ________________________ A v A ________________________ | | | | | | B | | | | | | | | | | | B ________________________ ||||||||||||||||||||||||||||||| C ||||||||||||||||||||||||||||||| C ________________________ The degrees are marked by vertical lines running from C to A and are not numbered in any way. The half degrees are marked by vertical lines running from C to a point half way between A and B. The 10' marks are vertical lines running from C to B. The Vernier is marked thus: - The minute lines run from A to C, the half minute (30") lines from C to a point half way between B and A, and the 10" lines from B to C. [[drawing of Vernier scale similar to the following...]] C________________C ||||||||||||||||||||||||| ||||||||||||||||||||||||| B________________B | | | | | | | | | | | | | | A________________A ^ 2 4 The 0 is marked with a [[diamond-shaped mark]] below A and the even minutes up to 10 are marked 2, 4, 6 etc. below A. The odd minutes are not numbered.