DETERMINATION OF THE QUALITY OF WOODS. 261 



In the ahoce example — 



Block (1) The proportion is 60 : 40 : hence the reduced area 

 ■c is obtained by means of the equation — 



40 : GO = '100 : r and r =: '-^^^^ ^^ = 800 acres. 



,, (2) 40 : oO = 100 : r ,, .r = -^ — =l'2ij ,, 



40 



„ ^8) 40: 40 = 200 :.r „ ,r = :^-^='200 „ 



„ (4) 40 : 80 = 500 : r „ .r = '^-i^-^ = 375 „ 



40 



Total = 1,000 acres. 



If now the forest is to be divided into annual coupes of 

 equal yield capacity, the area to be placed in each is also 

 obtained by calculating with the inverse proportion of the 

 qualities. 



Example. — The above forest shall be divided into ten 

 coupes of equal yield capacity ; then the reduced area of 



each coupe is = — .-^ = 100 acres. The real area of a coupe 



in each block is calculated as follows : — 



Block (1) 60 : 40 = 100 : x and x = i^^l^ = 66-67 acres. 



bO 



„ (2)50:40=100:^- „ .r = ^^^^i^= SO'OO „ 



oO 



„ (8) 40 : 40 = 100 : x „ x = ^^^><100 _ lOQ-OO „ 



„ (4) 80 : 40 = 100 : r „ .r = —^^-^^ = 188-88 „ 



80 



or, 



Coupe No. 1 = 66-67 = 66-67 acres 



„ 2= 66-67 = 66-67 „ 



„ 'd=z 66-66 = 66-66 „ 



,,4= 80-00 = SO-00 ,, Fnnii l)luck Xo. 2. 



Taken from block 

 No. 1. 



