PERCENTAGE COMPARISONS 279 



The following examples will show the percentage com- 

 parison between the foregoing methods. 



A log is 28 J l feet long by 20 inches quarter girth (at half 

 its length) over bark. Taper equals I inch quarter girth in 

 7 feet length. Then the 



True contents (over bark) : 



by the 1 13 divisor = 2OX2QX28 * 



or, by the formula 



= 100 cub. ft. 



J2 V7T 



3.14159x144 452-38896 



= loo cub. ft. (nearly). 

 .- 



* p , _ circumference _ 80^ 



7T 7T . 



True contents (under bark) : 



= ioo- 

 = 83^ cub. ft. 



This shows a deduction of i6f per cent, as compared with 

 the true contents over bark. 



However, usually in practice ij inches would be deducted 

 for bark on this particular log, and thus the contents would 

 be: 



I8 ^ xi8 ^ x 28 = 854 cub. ft. 



By Quarter Girth Measurement (over bark) : 



Contents = 2OX2 x 28* 

 144 



72 

 = 78^ cub. ft. (over bark). 



This shows a deduction of 2i per cent, as compared with 

 the true contents. 



1 This particular length is taken in order to bring the contents to 100. 



