A treatise on surveying, comprising the theory and the practice (1906)
Gillespie, William Mitchell, 1816-1868, Staley, Cady, 1840- · New York D. Appleton · leaf 37
little bettertelescope than that usedon the five- to seven-milelines. If the atmosphereis clear, a four-inch polemay be seen at a distanceof 20 miles, especially ifthe signal has a flag ortarget so that it may bereadily identified. A flut-tering flag is an excellent object to catch the eye when… … SIGNALS. 27 Fig. 440. of board along one of the diagonals of a square piece of cloth, andthen nail this strip to the signal pole, taking care to center it andalso to make it perpendicu-lar to the axis of the pole,then tack the other two cor-ners of the square of cloth tothe signal pole, so that…
Surveying
Internet Archive · Gerstein Library, University of Toronto · Public Domain Mark 1.0. Free to use for anything.
