CUBIC LOG MEASURE 217 



Method oj cubing logs by the measurement of the length and of the middle 

 diameters. 



To cube logs, one method requires the measurement of the average 

 diameter of the log at its middle point and the length. The volume 

 of the log is obtained by multiplying the area of the circle correspond- 

 ing to the middle diameter of the log by the length : — 



in which V is the volume of the log in cubic feet, B^ the area of the 

 middle cross section in square feet, and L the length in feet. 



Example : Suppose a log to have a middle diameter of 15 inches and 

 a length of 30 feet. One finds in a table of areas of circles (giving the 

 diameter in inches and the area in square feet) the area corresponding 

 to 15 inches, namely, 1.227 ; then V = 1.227 X 30 = 36.8 cubic feet. 



This method is very simple, because it requires only two measure- 

 ments of the log — the diameter at the middle and the length. Tables 

 showing the areas of circles in these units are readily accessible, and 

 also tables showing the cubic contents of logs of different middle diam- 

 eters and lengths, so that there is no computation necessary. 



Method of cubing logs by 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 end diameters by the length : — 



2 



in which V is 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 : — 



V =1396+1767 ^ j2 = 18.97 cu. ft. 



