A treatise on surveying ; in which the theory and practice are fully explained (1860)
Alsop, Samuel · Philadelphia, E. C. & J. Biddle & co. · leaf 103
number Aof divisions on the vernier : the number fthat occupies the same space on the arc, H—in this case, as 12 to 11. Take fromthe table of chords the chord of 1° or ^°, as the case may be,and multiply it by the length of EG; lay off the product onGF, thus determining the points 1, 2, 3, &c,… … Sec. V.] INSTRUMENTS AND FIELD OPERATIONS. 101 division on AB ; then, keeping it pressed against the needle,bring it successively to the other points on GIF, and drawthe corresponding divisions on AB. The arc will then bedivided. In the same way, resting the ruler against theneedle, and bringing it…
Surveying
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