30 Forestry Quarterly. 



feet. Dividing eighteen by four we have four hundred and fifty 

 per cent, increase over Doyle Rule. 



The above tables show conclusively that the degree of inac- 

 curacy of the old rules varies with the size of the logs; hence 

 the addition of any certain percentage to the scale of a lot of 

 logs by either of the old rules will be unjust one way or the other 

 unless the average diameter of the logs happens to be just what 

 it should be to make the percentage hold good. 



Thus, the Pennsylvania Department's method of adding twenty- 

 five per cent, to the scale of logs by the Doyle Rule is fairly 

 accurate when the logs average in the neighborhood of thirteen 

 inches in diameter inside the bark at the small end ; but the ap- 

 plication of this method to logs averaging over thirteen inches 

 in diameter is unfair to the buyer, while its application to logs 

 under thirteen inches is decidedly unfair to the seller under these 

 milling conditions. (See Table 3). 



From this it can be seen that it is almost impossible to so 

 modify the old rules as to make them fit present conditions. 

 The Scribner Rule, it is true, does not make such a poor show- 

 ing as some of the other age-moulded rules, but it leaves much 

 to be desired. The Doyle Rule is altogether indefensible from 

 any point of view, yet it is used more frequently (in Pennsyl- 

 vania, at least) than any other rule. 



The remedy seems to lie not in the construction of a new rule — 

 of these there is already a superabundance — but in a change of 

 sales methods so that all sales may be based on cubic volume. 

 Each purchaser could then determine his own converting factor * 

 subject to local grades and methods. 



The present slipshod arrangement of trying to modify the 

 old rules is only putting off until to-morrow what should be 

 done to-day, and what must be done eventually. 



*The converting factor from used volume in Cubic feet inside bark to 

 board feet mill cut is 5.3 and the outside bark factor is 4.7 for this mill in 

 this lot of logs. 



