FORESTRY 



A BCD. Rectangular frame. 



E. Folding mirror to reflect scale and plumb-line. 



gS. Plumb-line. 



Eye-piece. 



b. The objective a cross wire used in sighting. 

 ge. Vertical scale adjusted to distance from object. 

 CD/i. Horizontal or marginal rule upon which is 

 shown height of tree. 



Weisis Hypsometer (Fig. 27) is constructed on exactly the 

 same principle. It is even handier than Faustmann's instru- 

 ment, though both are simple and reliable. Sighting is here 

 effected through a metal tube, on the side of which is fastened 

 a toothed scale, upon which the plumb-line indicates the 

 height. The units of distance from the observer to the base 

 of the tree must be shown upon a second scale that which 

 has its position at right-angles to the " height scale " - 

 before the operator commences sighting. 



In order to ascertain the condition of a wood, it is necessary 

 to take into consideration the growing stock, its age and in- 

 crement, and the quality of the locality (i.e. soil and situation). 



