Surveying ; a manual of practical instruction in the art of plane surveying, including plotting, leveling, triangulation, line running, cross-sectioning, traversing, and other details of field work (1910)
American School of Correspondence, Phillips, Alfred Edward, 1863- [from old catalog] · Chicago, American school of correspondence · leaf 43
evel would be limited by the length of rod.In using the Abuey instrument it is only necessary to mark theheight of the eyes uj)on the rod. In sighting upon the rod, withthe horizontal line coinciding with the mark upon the rod, move thevertical circle until the bubble is in the center of the tube.… … Fig. 27. ground, multij)ly this distance by the sine of the vertical angle toget the diUereuce of elevation. The most satisfactory method of using this instrument is inconnection with a straijiht edge from 8 to 10 feet in lencrth. Thestraight edge is laid upon the gi-oiind parallel to the direction…
Surveying
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