The Measuretnent of Saw Logs 89 



taken. The crook in the twelve feet towards the small end of 

 the log was also measured by applying a straight-edge to the 

 side showing the greatest curvature. Unless it is desired to dis- 

 cover the cmise of any variation from the rule scale the measure- 

 ment of the crook and the butt diameter may of course be 

 omitted. 



Further procedure can perhaps be more easily made clear by 

 assuming a concrete case. For this purpose let the task be to 

 determine the correction to be made — if any — in adapting the 

 rule for specially accurate work with, say, Adirondack spruce. 

 lyCt the assumed conditions be as follows : 



I^ogs sawn (16 feet long) 1000 



Average diameter at top , 10 inches 



Kerf cut by saw used ^ inch 



Allowance for shrinkage : Y^g inch 



Scale by International }i Rule 71,585 ft. B.M. 



Scale adapted for yVi^^ch kerf (see page 84) 68,006 " " 



Actual product after manufacture 69,606 " " 



Over-run of scale by saw cut 1,600" " 



Average over- run per log 1.6 " " 



By using the rule formula it will be found that with a y^g-inch 

 kerf it takes an increase of just .1 inch in the diameter of a 

 lo-inch log to increase the scale 1.6 feet board measure. In 

 other words, if the above supposed case were a real one, the 

 saving in the edging waste of 1.6 feet B.M. per log on account 

 of the greater straightness of the logs would have as great an 

 effect on the product in sawn lumber as an increase of . i inch 

 in the diameter of all the logs would have on the scale. The 

 application is obvious. If it be desired to adapt the Interna- 

 tional Rule for logs sawing out as economically as in the sup- 

 posed case above, the zero point of the graduations on the 

 scaling stick must be moved .1 inch to the right so that from o 

 to the I -inch mark on the scale, the actual distance will be but 

 .9 inch. So adjusted, the scaling stick would be a local rule for 

 the species or the locality giving as favorable results from 

 actual mill tests as have been assumed for illustration purposes. 



Mill Test with White Pine. The results of a test with white 

 pine logs made in the summer of 1905 on the Ottawa under 

 ordinary commercial conditions will be of interest. In scaling 



