98 LOG SCALING FOR BOARD MEASURE 



standard tapers, calipers must be brought into use in scaling. The 

 calipers employed in scaling logs by the Blodgett rule are equipped with 

 a wheel of 10 spokes, one revolution measuring 5 feet in length (§34), 



The greatest drawback to a caliper scale is the necessity of determin- 

 ing the width of bark, doubling this, and subtracting to get the scaling 

 diameter of the log. When all logs are calipered, it is a common prac- 

 tice to determine the average width of bark of the species and region, 

 and deduct twice this fixed amount on all logs regardless of variations 

 in actual bark thickness, relying on the law of averages to secure a true 

 scale. For the Blodgett rule, |-inch for each bark is allowed and the 

 calipers are adjusted to read the diameter inside bark direct. On the 

 Big Sandy River in Kentucky (Big Sandy Cube Rule) the allowance is 

 1 inch for each bark.^ 



85. Scale Records. The tally is the record kept of the logs by the scaler or his 

 assistant, the tally man.^ The tally may consist merely of a record of diameter 

 and length of each log. From this the full scale is easily computed at camp. But 

 the system prevents deductions for defects from each log separately, and is used 

 only where such discounts are not made, or are made either as a per cent of total 

 scale, or by reducing the length or diameter of the log. This primitive method 

 of scaUng has been largely replaced by the plan of recording the board-foot contents 

 of each log when scaled. From the full scale, deduction is made for defect, and the 

 net or sound scale recorded. For long logs scaled in two or more sections, only 

 the sum of these volumes is set down, giving the total scale for the log as one piece 

 and thus keeping the count intact. The purpose in this is to obtain a tally of 

 the exact number of pieces scaled as well as their total contents. 



To still further insure an accurate record, logs are numbered serially, with 

 crayon, coinciding with printed numbers in the scale-book. This enables a check 

 scaler to re-scale and compare individual logs, or any number of logs, with the 

 original scale to determine the per cent of error and the specific faults in practice. 

 Without such enumeration, the entire number must be re-scaled to obtain a check, 

 and specific errors are not shown. The method of numbering is cumbersome where 

 large quantities of very small logs are handled, but it is the only plan by which a 

 uniform standard of scaling may be attained by a force of several scalers. 



1 A second method, employed in Maine in scaling cubic contents, is to assume 

 that the volume of bark is 12§ per cent of the total volume of the tree with bark. 

 The diameter outside bark is measured direct, and the volumes given on the rule 

 are computed to express the contents of wood alone. 



Bark is never removed, in scaling, to permit the calipering of the direct measure- 

 ment inside bark, as this process is too time consuming. The Tiemann log rule 

 (§ 63) which applies to middle diameter inside bark, if used commercially, would 

 probably be applied by the common method of deducting fixed widths of bark, 

 to be regulated by measurements taken of the species and locality. This practice 

 permits of an additional source of variation in measuring diameters (§ 29) through 

 the bark on individual logs being thicker or thinner than the arbitrary measure- 

 ment. 



2 Scalers usually work alone, preferring the extra labor to the risk of errors 

 made in the record by incompetent tally men. 



