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 46
Sextant. INSTBU3IEXTS •27 number of degrees of the principal arc has been marked off,into a slightly different number of divisions to that occupiedby the same space in the arc itself; then, by noticing wherethe line on the arc coincides with a line on the small arc, orvernier, the reading can be at… … Fig. 33.—Reading Micrometer for Theodolite.{From Text Boole of Topographical and Geographical Surveying.) time past now have been fitted with a micrometer microscopefor reading. This micrometer arrangement, which was apparently firstsuggested by a young astronomer named Gascoigne (whofell at…
Cartography · Surveying
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