Putnam, G. R. (George Rockwell), b. 1865 · New York, J. Wiley & Sons; [etc.] · leaf 150
O H … Horizontal Sexta?it Angles 135 instruments are required and the conditions are notalways favorable. It is so valuable a method, however,that it should be used, when necessary, on every well-equipped vessel. A single horizontal angle takenwith a sextant between objects, as two lighthouses,defines…
Nautical charts
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