CUBIC MEASURE. 45 



METHOD OF CUBING LOGS BY THE MEASUREMENT 

 OF THE LENGTH AND END DIAMETERS. 



By this method the diameters of the two ends of the log and its 

 length are measured. The volume is obtained by multiplying the 

 average of the areas of circles that correspond to the end diameters 

 by the length. Expressed as a formula: 



in which Vis the volume of the log in cubic feet, B and b are the 

 areas in square feet that correspond to the diameters of the two ends, 

 and L is the length in feet. 



EXAMPLE : A log is 12 feet long and the diameters at the ends are 

 16 and 18 inches. The areas that correspond to the end diameters 

 are found in a table of circular areas, and used in the formula, as 

 follows: 



F= 1.396+1.767 X12=1897 cubic feet 



This method requires one more measurement than the previous and 

 is therefore not as rapid for ordinary work in commercial scaling. 

 It is, however, a very convenient formula for determining the con- 

 tents of logs where it is not possible to take the measurement at the 

 middle, as on logs piled on a skidway. 



