HYPSOMETERS BASED ON PENDULUM OR PLUMB-BOB 239 



point, and one to the base. In this case the actual angle from station 

 to point on tree is read, and indicates the height in per cent of the hori- 

 zontal distance. At 100 feet distance, an 80 per cent angle to tip 

 equals a height of 80 feet above the eye. If the lower angle to base is 



Fig. 45. — The Abney hand level and clinometer. 



now 5 per cent, the additional height is 5 feet, total height 85 feet. 

 At 50-foot distance these per cents applied to 50 feet give a total height 

 of 42^ feet. It is convenient therefore to read heights by this method 

 from distances easily converted into equivalent heights. 



Fig. 46. — Goulier's Clinometer. 



197. Hypsometers Based on the Pendulum or Plumb-bob. These 

 angles can be read as easily from a pendulum, with graduated arc placed 

 below. A clinometer constructed on this principle, and used as a 

 hypsometer, is illustrated in Fig. 46. 



