A treatise on land-surveying; comprising the theory developed from five elementary principles; and the practice with the chain alone, the compass, the transit, the theodolite, the plane table, &c. Illustrated by four hundred engravings, and a magnetic chart (1875)
Gillespie, W. M. (William Mitchell), 1816-1868 · New York, D. Appleton · leaf 197
190 COMPASS SURVEYING. [part III … according to the locality. Observations of the amount and thedirection of this variation have been made m nearly all parts of theworld. In the United States the Variation in the Eastern Stateais Westerly, and in the Western States is Easterly, as vsill begiven in detail, after the methods for…
Surveying
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![An illustration from L'optique divisée en trois livres : ou, l'On démontre d'une maniere aisée tout ce qui regarde 1. la propagation & les proprietez de la lumiere. 2. La vision. 3. La figure & la disposition des verres qui servent à la perfefectionner [sic] (1682)](https://img.insideoutlibrary.com/img/200/ia-loptiquedivise00ango-329-36.webp)
