166 A MANUAL FOR NORTHERN WOODSMEN 



by the face and adjust the hold till the end of the staff 

 just comes by the eye. The distance from the eye to the 

 staff and from the hand up to the end of the staff are now 

 equal. Go off from the tree to be measured, holding the 

 staff erect, until you can sight by the fist to the base of the 

 tree and by the top of the staff to the top of the tree. Pace 

 or measure to the tree and this will give its height. 



4. The Abney clinometer, shown on page 93 of this 

 work, may be used for height measurement in much the 

 same manner. Set the level tube at an angle of 45 with 

 the line of sight and go off from the tree on a level with 



FAUSTMANN ? S HEIGHT MEASURE 



its base until, sighting at the top of the tree, you see by 

 the bubble that the tube is level. The distance from the 

 observer to the tree is then equal to the tree's height. 



5. A second method employing the same instrument 

 is as follows : Stand at a point where both the top and the 

 base of the tree can be seen and at some convenient dis- 

 tance from it, as 100 feet. Sight to the top of the tree and 

 observe the angle of inclination, and again to the base of 

 the tree, observing that angle also. Go into the table of 

 tangents with the angles in turn, find the decimals corre- 

 sponding, and multiply by the length of base. The sum 

 of the two figures is the total height of the tree. 



