Maps and map-making; three lectures delivered under the auspices of the Royal geographical society (1910)
Reeves, Edward Ayearst, 1862-1945, Royal Geographical Society (Great Britain) · London, The Royal geographical society · leaf 42
Fig. 27.—Principle of ArtificialHorizon. Fig. 28.—Pocket Sextant. line on land, and so an Artificial Horizon has to be used, andthen the angle measured with a sextant between the sunitself and its reflected image in the artificial horizon, dividedby two, is the altitude. The artificial horizon is…
Cartography · Surveying
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