A treatise on surveying, comprising the theory and the practice ; (1887)
Gillespie, W. M. (William Mitchell), 1816-1868, Staley, Cady, 1840- [from old catalog] ed · New York, D. Appleton and company · leaf 227
the left-hand vernier is to be read, as in Art. 312; but when thedegrees are counted to the right, from the 360° line, the right-hand vernier is to be used. 319. Oompass-Vernier. Another form of double vernier, oftenapplied to the compass, is shown in Fig. 229. The limb is Fig. 229. — ^ 2|0 25 30… … divided to half-degrees, and the vernier reads to minutes, 30parts on it being equal to 31 on the limb. But the vernier isonly half as long as in the previous case, going only to 15, theupper figures on one half being a sort of continuation of the lowerfigures on the other half. Thus, in moving the…
Surveying
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