The theory and practice of surveying. Designed for the use of surveyors and engineers generally, but especially for the use of students in engineering (1886)
Johnson, J. B. (John Butler), 1850-1902 · New York, J. Wiley & sons · leaf 92
with the axis for holding it to agiven pointing or for moving it horizontally while clamped.The attached bubble enables the line of sight in the telescopeto be brought into a horizontal position. The construction of the instrument is best shown by thesectional view given in Fig. 13. The objective… … formed at the plane of the cross-wires, which are attached to thereticule held in place by the capstan-screws shown in the cut. The 62 SURVEYING.
Surveying
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