300 Forestry Quarterly. 



i.op"= 3. the constant up (or 100 log 3) 



l.op'^^: 4, the constant np 



i.op"=: 5, the constant np 



i.opi^=: 6, the constant np 



i.op"= 7, the constant np 



i.op"= 8, the constant np 



i.op"r= 9, the constant np 



i,op"=rio, the constant np 

 This is an easily memorized logarithmic table, li np does not 

 coincide with any of these values, a simple interpolation between 

 two values is possible: e. g. i.o258o:=7.3. since np=200, and 

 200^195=100 log 7 

 <^2io=ioo log 8 

 Various logarithmic relations can then be used to secure solutions 

 lying outside of these given numbers. E. g. when in the funda- 

 mental equation i,op"=C C is the unknown, say i.04i*^r=x 

 since w/'=40=iio — 70=100 log (3^)^ hence xr:=i.5 app. (1.48 



exactly). 



Similarly. 1.03^*^^= x .; since ;f/>=300=2304- 70=100 log 



(10x2), hence x=:20 (19.2). If in the equation n is unknown e. 



70x4 

 g. 1,035'^= 15.68 .:. since C nearly 16=2'*, x= 80 (pre- 



2x9, _ 70+220-230 

 cisely) ; or again 1.03^=1.8 . : since C= hence x — 



:=20 (precisely). 



The shortcuts for the various rent formulae are worked out 

 and examples in application given. We give one of the latter: 

 The celebrated Spessart oak brought for I class logs in 1836, 23 

 Mk; in 1907, 185 Mk; what is the price increment rate in the 71 

 years 



185 

 i-op^i=— --8.0435 



100 log 8.0435 210 

 p= =-;7- appr.=2.96 (2.98 actually) 



The author believes that for a clearer understanding of forest- 

 valuation and statics at least this short cut procedure may be help- 

 ful. 



Zur Zinseszinsrechnung. Allgemeine Forst-u. Jagdzeitung. January, 

 1912. Pp. 11-19. 



