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 403
ingtwo graduated circles : one vertical, having a weight attached so as to keep it in the same vertical posi-tion when in use ; and the other, ahorizontal graduated circle, madelight and carried around by a mag-netic needle, so that the instrumentcan be used as a compass as well asa slope or… … Fig. 421.
Surveying
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