184 PRINCIPLES OF AMERICAN FORESTRY. 



long is equal in feet board measure to the square of the 

 diameter reduced by four. Thus a log twenty-four inches 

 in diameter and sixteen feet long would be estimated 

 as (24-4) X (24 -4) = 400 feet board measure. If it is 

 eighteen feet long it would be estimated as 400 X-Jf or 

 450 fe-et. This rule is so simple that any one acquainted 

 with figures can easily construct a working table. A table 

 of this sort is given on page 185. 



Scribner's and Doyle's Rules are not Adapted to the 

 measurement of logs that are to be used for paper-pulp, 

 and here probably the fairest method is to caliper the 

 logs in the middle, allowing for the bark, and compute 

 the volume as a cylinder with that diameter. This gives 

 a close approximation of the cubic contents, which is what 

 is wanted. In the case of long logs that taper very fast, 

 these rules will also fail to give a fair measurement, and 

 in such cases logs will frequently scale more by these rules 

 after they are shortened a few feet, which is absurd. These 

 points should be kept in mind in using them. The Dimick 

 rule is used in the Adirondacks for spruce pulp wood. 



The New Hampshire Rule for Measuring Timber is in 

 use in New Hampshire. Here an artificial cubic foot 

 has been made by law and is equal to 1.4 of the standard 

 cubic foot. This is a caliper rule, which gives the con- 

 tents of a log from length and diameter at middle, seven- 

 eighths of an inch by the structure of the rule being thrown 

 out for the bark. The law on the subject is as follows: 



"All round ship timber shall be measured according to 

 the following rule: A stick of timber sixteen inches in 

 diameter and twelve inches in length shall constitute one 

 cubic foot, and in the same ratio for any other size and 

 quantity; forty feet shall constitute one ton. 



" All round timber the quantity of which is estimated by 

 the thousand shall be measured according to the following 

 rule: A stick of timber sixteen inches in diameter and 



