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 374
525. Troughtons Level. In this the bubble-tube is perma-nently fastened in the top of the telescope-tube. It is adjusted bythe peg method, or some similar one, the cross-hair being movedup or down until the observation gives the true difference of heightof the pegs when the bubble is in the center.… … 526. Gravatts Level, or the Dumpy Level. Its diameter isvery great, thus giving more light. Its bubble is on the top, andcan be seen in a small in-clined mirror, by the ob-server. It also has across-level. 527. Lenoirs Level. In this, the telescope carries,at each end, a steel block,whose upper and…
Surveying
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![An illustration from Bicknell's village builder. Elevations and plans for cottages, villas, suburban residences, farm houses [etc.] also exterior and interior details for public and private buildings, with approved forms of contracts and specifications. Containing fifty-five plates drawn to scale (1872)](https://img.insideoutlibrary.com/img/200/ia-bicknellsvillage00bick-195-183.webp)
