26 



]NSTRT-:\rEXTS TSED IX MENSURATION. 



For convenience sake, a little table accompanies the instru- 

 ment, in which the heights, corresponding to various distances 

 and upper plus lower angles, are given. In order to reduce 

 this table as much as possible, it gives only upper angles from 

 40° to 50° in intervals of 2°, and lower angles from 0° to 25° in 

 intervals of 5°. This necessitates placing a staff, on which 

 feet are marked by alternate colours, alongside the tree, so as 

 to read off the distance between the lower ray of the lower 

 angle and the foot of the tree, a distance which has to be 

 added to the height taken from the table. 



The instrument is at tlie same time an admirable clino- 

 meter, with which the angles of slopes can be measured and 



y/Tz^ 



Fiff. 18. 



roads laid out. The author has used the instrument exten- 

 sively, both for the measurement of the height of trees, and 

 for the laying out of forest roads ; he has arrived at the 

 conclusion, that it is decidedly the most useful of similar 

 instruments, which are known to him. The instrument works 

 accurately, and much quicker than the reader would imagine ; 

 besides, its strong const-ruction renders it admirably adapted 

 for forest work. 



0. luHtrumentsfoy ihe Inrcct JSIeasurevK-nt of the Volnme. 



For this purpose the xylometer, either alone or in com- 

 bination with a scale, is used. The method is based upon 



