A treatise on surveying, comprising the theory and the practice (1906)
Gillespie, William Mitchell, 1816-1868, Staley, Cady, 1840- · New York D. Appleton · leaf 40
of the observing station. Whether the correction for phase is positive or negative is readilyseen from the relative positions of the sun and signal. For directionsincreasing from left to right, the correction for phase is minus whenthe sun is to the right of the signal and plus when it is on the… … recourse to some other device. This is accomplished by theheliotrope, which is an instrument for reflecting the suns rays.Fig. 444 shows such an instrument, consisting simply of a mirror 30 GEODESY. Fig. 444>. and directing arrangement attached to a telescope. The mirror isprovided with two…
Surveying
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