44 THE WOODSMAN’S HANDBOOK. 
A cubic unit, either the cubic foot or cubic meter, ultimately will 
be in common use for the commercial measurement of timber. 
This will come about with the increase of the value of timber. 
When the whole log, including slabs, can be used, the owner can 
not afford to sell his logs purely on a basis of an estimated product 
in manufactured boards. Ii logs are bought according to their solid 
contents, though they may not cost more, yet the buyer will feel 
that he pays for the material he wastes and therefore will be more 
eager to utilize it. 
There are a number of methods of iGaneee the solid contents 
of logs in cubic feet. The two methods in most common use for 
commercial work are given in this book. Other methods, designed 
for scientific work, are discussed at length in treatises on forest 
mensuration. 
METHOD OF CUBING LOGS BY THE MEASUREMENT 
OF THE LENGTH AND OF THE MIDDLE DIAMETERS. 
To cube logs, one method requires the measurement of the aver- 
age 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 
corresponding to the middle diameter of the log by thelength. Ex- 
pressed algebraically: & 
V=B, X L, 
in which V is the volume of the log in cubic feet, B, the area of the 
_ middle cross section in square feet, and Z the length i in feet. | 
EXAMPLE: Suppose a log to have a middle diameter of 15 inches 
and a length of 30 feet. One findsina table of areas of circles (giv- 
ing the diameter in inches and the areain square feet) the areacor- 
responding to 15 inches, namely, 1.227; then V=1.227X30=36.8 | 
cubic feet. 
This method is very simple, because it requires only two meas- | 
urements of the log—the diameter at the middle and the length. 
Tables showing the areas of circles in these units are readily acces- | 
sible, and also tables showing the cubic contents of logs of different 
middle diameters and lengths, so that there is no computation © 
necessary. (See table 5.) 
