DISCUSSION OF LOG RULES. 41 



To find how many board feet as shown by the Vermont rule are 

 equivalent to a standard of the Nineteen Inch rule : 



(1 .363) - - X 13 = 195.5 



4b 



Therefore, 195.5 board feet as shown by the Vermont rule equals one 

 standard of the Ninteen Inch Standard Rule. This relation holds for all 

 sized logs. In like manner, reducing factors for the.Constantine, Saco 

 River, Derby, Square of Three-quarters, Partridge, Still well, Ake, 

 Square of Two-thirds, Orange River and Cumberland River rules may 

 be obtained. All rules of the above form have definite reducing factors 

 which apply to all logs, regardless of size, and to any aggregate scale 

 representing any number of logs. 



Given: The Nineteen Inch Standard Rule - - F, in standards, 

 to find a log rule equivalent to it when one standard = 200 board feet: 



71 19 2 



n x 19 2 X 13 

 c = .350 



Therefore: (1 .350) - L = B.M. is an equivalent rule for the 

 4 X 1-" 



Nineteen Inch Standard when a standard unit is equal to 200 board 

 feet. In like manner equivalent rules for other standard rules may be 

 obtained when the value of the unit is given in board feet. 



For instance, the Blodgett rule allows 10 board feet for the equivalent 

 of one standard, and the resulting rule which is equivalent to the 

 Bodgett under these conditions is 



(1 .423) - L = B.M. is the equivalent for the cube rule when 



4 X 12 

 its standard unit = 12 board feet. 



It must be borne in mind that log rules of the form 



are very poor rules for measuring the number of board feet of lumber 

 that can be sawed from logs of different sizes, and that the three distinct 

 types of rules discussed under the heading "A Comparison of Three 

 Different Types of Log Rules" can have no common reducing factor for 



