go Forestry Quarterly 



the logs for the following comparative statement, all fractions of 

 inches in the measured diameters were disregarded if of the 

 even half inch or less, while all greater than the half were 

 counted as full inches, except in the case of the Champlain scale 

 where all fractions were disregarded as directed hy the maker 

 of the rule. The logs were cut almost entirely to inch boards 

 (i yV inches thick) by a band saw cutting a ^-inch kerf : 



Over-run ( + ; or under-run (— ) of Saw Cut as 

 compared with scale by 



The groups of smaller logs are over- lapped somewhat to show 

 intermediate steps in the decreasing error of the Doyle scale as 

 the logs grow larger. The io-17-inch group of 104 logs repre- 

 sents the average log as cut on Ontario public lands in 1904, the 

 scale of the average log being 61 feet according to Doyle. The 

 Doyle rule is of course increasingly unsatisfactory as a measure 

 of log values as the average log milled grows smaller. The de- 

 crease in the size of the average pine log cut in Ontario has been 

 35% during the last 12 years. The Scribner rule is much less 

 extreme than the Doyle but is quite out of touch with modern 

 conditions. The theoretical allowance for edging used in the 

 computation of the Champlain rule was a i-inch board from the 

 centre of the logs .sawn. This is equivalent to about .3 foot 

 board measure per square foot of bark surface, and is much too 

 low even for the straightest, smoothest logs. The absence of 

 any allowance for taper in the scaling score is equivalent to 

 adding at least .5 ft. B.M per sq. ft. of bark surface when i6-ft. 

 logs are sawn. Where the fractions of inches are all disregarded 

 in measuring the diameters in scaling, this edging allowance is 

 further bonused to the extent of about .22 ft. B.M. or a total edg- 

 ing allowance of a trifle over one foot board measure per square 

 foot of bark surface, which is larger than necessary. Were the 

 Champlain rule a ^-inch kerf rule as intended by its author, the 

 band saw cut should have over-run its scale 10 per cent, through- 



