A treatise on surveying ; in which the theory and practice are fully explained (1860)
Alsop, Samuel · Philadelphia, E. C. & J. Biddle & co. · leaf 101
y nine onthe arc. The reading is therefore to -^ of 30 minutes = 1minute. The zero of the vernier stands between 41° 30and 42°. On looking along the vernier, it is seen that thefifth and sixth lines coincide about equally well. The ver-nier therefore reads 41° 35r 30 179. Reading backwards.…
Surveying
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