Hydrographical surveying : a description of means and methods employed in constructing marine charts (1920)
Wharton, W. J. L. (William James Lloyd), 1843-1905, Field, Arthur Mostyn, 1855- · London : J. Murray · leaf 165
s, which are invisible from eachother, ivith an intermediate station visible from one of them, andfrom which the inaccessible object is also visible. From the shipat anchor midway betiveen the astronomical j)ositions all pointsare visible. In Fig. 34, A and B are the terminal astronomical… … A Observers being at the masthead and provided with Galtonssun-signals for flashing, if necessary, other observers withtheodoHtes and hehostats are stationed at A, D, and B. At a preconcerted signal (the dipping of a flag, letting fallsquare sails, or at a given moment by comparison of…
Hydrographic surveying · Nautical charts
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