. Forest mensuration. Fig. 45.—The Abney hand level and clinometer. now 5 per cent, the additional height is 5 feet, total height 85 50-foot distance these per cents applied to 50 feet give a total heightof 42| feet. It is convenient therefore to read heights by this methodfrom distances easily converted into equivalent Fig. 46.—Gouliers Clinometer. 197. Hypsometers Based on the Pendulum or Plumb-bob. Theseangles can be read as easily from a pendulum, with graduated arc placedbelow. A clinometer constructed on this principle, and used as ahypsometer, is illustrated in Fig. 46
. Forest mensuration. Fig. 45.—The Abney hand level and clinometer. now 5 per cent, the additional height is 5 feet, total height 85 50-foot distance these per cents applied to 50 feet give a total heightof 42| feet. It is convenient therefore to read heights by this methodfrom distances easily converted into equivalent Fig. 46.—Gouliers Clinometer. 197. Hypsometers Based on the Pendulum or Plumb-bob. Theseangles can be read as easily from a pendulum, with graduated arc placedbelow. A clinometer constructed on this principle, and used as ahypsometer, is illustrated in Fig. 46. 240 THE MEASUREMENT OF STANDING TREES The Fauslmann Hypsometer. Instead of graduating a circular arcin per cents, which requires a decreasing scale with increasing per cent(since the tangents of the angles increase faster than the angle), theheight scale corresponding with this arc may be placed on a straightarm as in other hypsometers (§ 195) and graduated evenly. The Faustmann hypsometer employs this principle of the pendulum,using a plumb-bob to determine the angles BAD and CAD, and indicat-ing the height of the tree above and below the point D by the intersec-tion of this plumb-bob string with the height scale on the base of thehypsometer. This instrument is illustrated in Fig. 47. Its methodof use is shown in Fig. 48. K
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectforestsandforestry
