SCRIBNER LOG RULE, 1846 73 



tional inches, can be cited the Baughman log rules for i-ineh and J-inch saw kerfs 

 respectively. The results obtained from these diagrams are so consistent that they 

 conform to the typical formula for a perfect log rule. 



„,, „,irfD-.87) 2 i , , . , , „ 



B.M. = . 81— — for |-inch kerf, 



4 12 



and 



B.M. = .90 — 1)2 — for |-inch kerf. 

 4 12 



In practice the use of these rules would give an under-run: i.e., the logs would not 

 saw out the scale. 



In these diagrams the minimum board was 4 inches, the lumber exactly 1 inch. 

 The 1-inch board was always placed in middle of diagram. Taper was neglected. 

 H. R. A. Baughman, Indianapolis, Ind. 



68. Scribner Log Rule, 1846. Synonym: Old Scribner. The 

 Scribner log rule is the oldest diagram rule now in general use. But for 

 the unfortunate substitution of the Doyle rule for this rule in Scribner's 

 Log and Lumber Book, its use would now be practically universal. 

 The rule held its own in the North and West, and is the legal standard 

 for Minnesota, Wisconsin, West Virginia, Oregon, Idaho, and Nevada. 

 It is the standard prescribed in timber sales on National Forests through- 

 out the West and by the Dominion Forestry Branch of Canada. 



The rule was published previous to 1846. The diagrams are for 

 1-inch lumber, and J inch saw kerf. The width of the minimum board 

 was not stated but the author modified an earlier edition of his rule by 

 increasing the allowance for slab on larger logs. As a result of this 

 unfortunate error, the rule gives a larger over-run on logs above 28 inches 

 than on smaller logs. The products of the diagrams were evidently 

 not evened off. The values, when plotted, show great irregularities, 

 but except for the factor just noted, the general tendency of the rule is 

 consistent. 



The original values were for logs from 12 to 44 inches in diameter in 

 sections 15 feet long, " the fractions of an inch inside the bark not 

 taken into the measurement." Taper is not considered on logs of the 

 lengths used. These factors the author intended to offset normal crook 

 and concealed defects. Values were then given for logs from 10 to 24 

 feet in length. 



Modification to a Decimal Rule. Two important changes in this rule 

 have been made to meet the demands for a universal log rule. It has 

 been changed to a decimal rule, and values for logs below 12 inches, 

 and above 44 inches have been added. The practice of modifying a log 

 rule in scaling by reducing it to even tens, in order to eliminate the col- 

 umn of unit feet in adding, is found in connection with several rules. 

 With the Scribner, instead of dropping odd feet, thus reducing the scale, 



