STANDARD HYPSOMETER. 



29 



METHOD OF USING THE FOREST SERVICE STANDARD 

 HYPSOMETER AND GRADEMETER. 



Stand 100 feet from the base of the tree which is to 

 be measured. 



The observer inserts the fingers of his left hand into 

 the loop of leather straps attached to the back of the 

 hypsometer, with 

 both straps inside 

 of the hand and 

 the instrument on 

 the back of the 

 lingers. Closing 

 the hand enables 

 him to grasp the 

 straps firmly. 

 The thumb is in 

 such a position as 

 readily to press 

 down the small 

 brass knob which 

 releases the cir- 

 cular pendulum 

 on the inside of 

 case. By an easy 

 motion of the el- 

 bow, the small 

 peephole is 

 brought close to the eye of the observer. The square 

 window, directly opposite the peephole, is pointed toward 

 the object whose height is to be determined. The light 

 enters from the large window on the face of instrument. 



FIG. 9. Method of sighting with standard hypsometer. 



