338 Forestry Quarterly 



factory enough, but where precision is required, as, for instance, in 

 height increment studies, also in sales on the stump, etc., it does 

 not satisfy; the sextant, with mirror, satisfies the requirement of 

 precision, but it works slowly, and neither of these instruments 

 is as good in stands with underbrush (cover of base!) as the old 

 Wimmenauer, which for all these years existed only in one exemplar 

 in the tool collection at Giessen, but can now be had from Sporhase 

 Giessen for 27 mk. 



The instrimient consists of a zinc or brass plate with a gradua- 

 tion as in the figure. Around point a a straight-edge turns, with 

 a rectangular section cut out, in which a fine wire is stretched. 

 At a, b, c sights are fixed. At d and e there are two holes through 

 which by screws to attach the instrimient to a staff. 



In measuring, position is taken between 30 to 100 feet from the 

 tree and the staff placed vertically by means of a plumb bob, when 

 the straight-edge lies horizontal. An assistant holds a rod with 

 two targets which are 2 meters apart, placed so high that the 

 horizontal sight line strikes either the higher or lower target. 

 Then sight c is sighted on the second disk when the length of the 

 stand line can be read off from the horizontal graduation, where 

 the wire ac cuts the zero line. Next, c is sighted on the top and 

 the height above the horizontal is read off on the vertical graduation 

 on the abscissa corresponding to the stand line. If, e. g., the 

 latter were 16 w, the reading might be, as in the figure, 10.5 w. 

 This is the height above the horizontal ; the lacking part is measured 

 directly by the assistant. 



The small squares being of 5 mm side, corresponding to 1 m 

 height or length of stand line, fifths and even tenths can be esti- 

 mated. The distance between the sights being about 22 cm, an 

 accurate sighting and reading is possible. 



The author considers this the all-round best instrument, easily 

 worked and accurate, more so than the Christen. 



Zwei Wimmenauer' sche Hohenmesser. Allgemeine Forst- und Jagd-Zeitung, 

 October-November, 1915, 234-9. 



Fischer bemoans the fact that estimating 



Helps contents of trees, logs, etc., has in Germany 



in become a lost art, the mechanical use of 



Estimating tables having destroyed the ability, and 



therewith the interest, to the detriment of 



original thinking. One reason for this inability he finds in the 



