74 



THE CONSTRUCTION OF LOG RULES 



the odd feet were rounded off to the nearest ten, values over 5 feet 

 being raised, while 5 feet and under are dropped. The average scale 

 of even a few logs by this method is practically identical with that 

 obtained by the original rule as the errors are compensating. This modi- 

 fied rule is known as the Scribner decimal rule. 



Exiensimi below 12 Inches. For values below 12 inches, the original rule pro- 

 vided no figures. The lack of a formula permitted individuals to supply their own 

 values for these sizes. As early as 1900, the Lufkin Rule Company tabulated the 

 decimal values then in use, under three schedules, termed A, B and C, shown below. 



To read in board feet, add a cipher to each figure. 



TABLE XII 

 Decimal Values Below 12 inches fok Scribner Log Rule 



Still other values resulted from the use of the full scale, rather than the decimal 

 form. In the Woodsman's Handbook, (1910 Forest Service), values for 16-foot logs 

 used by a company in New York (Santa Clara Lumber Co.) were published. These 

 values were adopted by the Canadian Forestry Branch in 1914. The State of Minne- 

 sota adopted standard values differing slightly from these figures. Wisconsin 

 adopted definite values by law for these sizes, conforming exactly to the Decimal "C" 

 scale given above. Idaho prescribes that the Scribner Decimal Scale be used with- 

 out specifying values and both "A" and "C" scales are in use in the state. In 

 Oregon and West Virginia the "Scribner Scale" is called for by statute, leaving the 

 question open for values below 12 inches. 



The weight of custom is at present in favor of the use of the Decimal "C" values 

 for this rule, and the utility of the Scribner Decimal Rule would be improved by a 

 universal adoption of this standard. 



Extension above 44 Inches. With the adoption of the rule by the Forest Service, 

 its use on the Pacific coast required an extension from 44 to 120 inches. In this 



