MEASUREMENT 



153 



with the eye what proportion this part bears to 

 the whole tree. 



The contents of the first 12 feet are found 

 by squaring the quarter-girth and dividing the 

 result by 12, e.g. at 6 feet from the ground the 

 circumference under bark is 36 inches, then 

 the quarter-girth is 9 inches, and 9 squared and 

 divided by 12 = 6*9, the cubic contents in feet 

 of the first 12 feet of the tree, for the cubic con- 

 tents equal the quarter-girth squared divided 

 by 144 and multiplied by the length in feet, i.e. 

 9 x 9 x 12 



12 x 12 



= 6-9. 



PLANTING TABLE 



Number of trees in an acre, defined by the Weights and 

 Measures Act, 1878, as containing 4,840 square yards. 



The formula is 



43,560 



distance apart x distance apart 



= number of trees. 



