GRAPHIC ANALYSIS. 27 



Let a = the average volume in board feet of %" C. and Better lumber 

 contained in an immature tree D inches in diameter breasthigh. 

 Similarly, let b = Moulding Stock. 

 c = No. 1 Shop, %". 

 d = D. Select and Better, V. 

 e = No. 1 Common, V . 

 f = No. 2 Common, V. 

 g = Shop, 1". 

 h = No. 2 Shop, %". 

 i = Shims. 

 j = Box, V. 

 k = Culls. 

 Z = Box %". 

 m = No. 3 Shop, %". 

 w = No. 3 Common, V . 

 o = Plank 3". 

 p = 4" x 4" and larger. 

 q = 2" x 4" and wider, No. 1 Dim. 

 D = Total volume in cubic feet inside bark from the stump to a 



height where the tree is 6" in diameter outside the bark. 

 As = Total volume in board feet, as shown by the Spaulding Log 



Rule. 

 A = Total volume in board feet of lumber of all grades "sawed 



out ' ' at mill. 



Av = Volume of high grade lumber. 

 Bv Volume of intermediate grade lumber. 

 Cv = Volume of low grade lumber. 



Then a + & + c + _______ o -{- p -{- q = A, total volume in board 



feet sawed out at mill. 

 a-\-~b-\-c-\-d = Av, high grade. 

 e -{- f-\- g -\-h-\- i= Bv, intermediate grade. 



j-\-k-\-l-{-m-\-n-}-o-\-p-\-q= ' Cv, low grade. 

 Av -f Bv + Cv = A. 



100 (a + b + c + d) 100 Av 



- = Ap, per cent of high grade 



A lumber sawed out. 



e + f + g + h + i) 100 Bv 



- = Bp, per cent of intermediate 



A grade lumber sawed out. 



- low grade lum- 



ber sawed out. 



Ap + Bp + Cp = 100%. 



.032a + .030Z> + .027c + .025d == Aval, value in dollars and cents 



of Av, the high grade lum- 

 ber produced. 



