160 



FOKESTRY WOEK 



measured. A plumb line suspended from the top of the 

 movable arm marks off on a scale at the bottom the 

 height in yards. This can be seen in a hinged mirror 

 attached to the frame without moving the instrument. 

 Whatever unit be taken in measuring the base line and 

 setting the upright arm, the answer will be the same. 



FIG. 16. FAUSTMAN'S HYPSOMETER. 

 \ * 



If metres, then the answer will be in metres. If yards 

 or feet, the answer will be in yards or feet respectively. 



With the telescope hypsometer, the movable arm is 

 set on the same principle and the sight taken through the 

 telescope. To allow the plumb line (a three-cornered 

 steel rod) to remain in place until the answer is read off, 



