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A record in a scalebook of important details serves two purposes: 



1 6 It is a guarantee of satisfactory vrork from the scaler and a guarantee 

 to the buyer and the seller that the work has been carefully done* When 

 a complete record is required of the species ^ diameter 3 lengthy cull de- 

 duction^ and net volume 5 the scaler will be more apt 'to make these measure- 

 ments carefully s Then too 5 the buyer and the seller $ knowing what these 

 measurements are 5 can if necessary recheck them for a group of logs* 



2 It serves as the basis of eliminating the personal element in scaling <» 

 If timber is defective s scaling is often a matter of individual judgment | 

 and since one unproved opinion is as good as another 5 it seems desirable 

 to have procedures rendered as uniform as possible by frequent check scales 

 made by a competent individual whose job it should be to maintain a high 

 scaling standard within the organization© Check-scaling is more effective 

 when the data for each log are completely recorded, since causes for 

 variation can then be corrected,, 



CONSTRUCTION OF A CUBIC- FOOT RULE 



How Much Taper All owance? 



Since many of the board-foot log rules in use assume that the contents of 

 a log are contained in a cylinder having a diameter equal to the top 

 diameter of the log, it becomes necessary when long logs are sealed to 

 apportion them into as equal lengths as possible, and scale the parts 

 separately after making allowance for taper a Some of the better built 

 board-foot log rules have an allowance for taper incorporated in the 

 rule which makes it unnecessary to scale long logs in short lengths* 



Taking into account convenience, pr ac tic ability , and accuracy, no better 

 principle can be f ollox-red in constructing a commercial cubic-foot rule 

 than to do as was done in making the best board-foot rules: choose the 

 top end of logs as the place for diameter measurement and incorporate a 

 taper allowance in the rule* 



A' taper of 0«5 inch in L feet is about average for every timber type in 

 the United States. This matter of taper was thoroughly discussed with 

 James W« Girard, assistant director of the forest survey* Mr Girard has 



