146 Forestry Quarterly. 



COMPARISON OF LOG RULES. 

 Sixteen-foot Logs. 



Diameters. 

 8 10 12 14 16 18 20 24 30 36 40 



Board Feet. 



Scribner, 32 54 79 114 159 213 280 404 657 923 1204 



Mass., 51 79 ii5 IS8 205 256 



Clement, 37 62 94 131 175 226 282 414 659 961 1 193 



Click, 55 60 91 129 173 223 280 413 660 965 1200 



Calcasieu, 50 73 99 129 163 201 290 453 



Cubic Foot Rules. One of the most encouraging steps in ad- 

 vance in log measurement is the agitation in Maine for a cubic 

 foot rule for the measurement of pulpwood. A committee ap- 

 pointed by the Legislature to investigate the subject of log meas- 

 urement has reported in favor of the cubic measure. 



A cubic feet rule has just been issued by Mr. Halbert G. Robin- 

 son, of Patten, Me. This is described in "The Measurement of 

 Logs" published by Thomas W. Burr Printing Co., Bangor, Me. 

 Robinson's table is based on the careful taper measurements of 

 4398 logs. The cubic contents of each was computed and then a 

 table of averages constructed on a basis of the middle diameter 

 of the logs and the length. It was found that the taper of spruce 

 averaged one inch for every 7.5 feet of length, for logs up to 40 

 feet long. Longer logs had a more rapid taper, so that the log 

 lengths were limited to 40 feet in the table. After arranging a 

 table by curves the author worked out a formula to express the 

 values and to aid in interpolating where the original data were 

 insufficient to permit of constructing curves. The formula is as 

 follows : 



3.i4i6XD 2 XLXi.049 



V=B*XLX 1.049=— —=0.824 D 2 L in 



4 

 which Bi is the sectional area at the middle, D is the diameter at 

 the middle, L the length, and 1.049 tne average taper of the log. 

 The author has presented the table in the form of a diagram 

 which may be used in constructing a caliper scale. A table is 

 also given showing the allowance which must be made for bark. 



