THE EXTENSION OF LOG RULES 21 



Directions : 



A. Method of Procedure. 



1. Find the difference in volume between the diameters of 14 and 16 



inches, 16 and 18 inches, 18 and 20 inches, 20 and 22 inches, 22 and 

 24 inches. 



2. Find the average of these differences. 



3. Find the average increase of these differences. 



4. To the vahie of a 24-ifich log as given in the table add the average 



difference found in 2, plus the average increase found in 3 and the 

 volume of a 26-inch log will be obtained. 



5. Secure the volume of a 28-inch log similarly by adding to the value of 



a 26-inch log the average difference plus twice the average increase. 



6. Continue this operation for all even diameters up to 36 inches and 



tabulate. 



7. The values for other log lengths may be extended in a similar manner 



and the values thus secured tabulated. 



B. References. Number 21. 



C. Discussion. 



1 From this problem and the preceding one would you say that there is 

 ever any justification for extending a log rule by tacking one rule 

 onto another? 



2. What are the different uses of plotted curves as illustrated in Prob- 

 lems 8, 9, 10 and 11. 



