CLEAEING THE CKOP 157 



This figure is squared, multiplied by the length, and 

 the product divided by 144 (the number of square inches 

 in a square foot), which gives the answer in feet. 



For instance, if a Scots Pine tree 50 feet long girths 

 48 inches at 25 feet, an allowance of ^ being made for 

 bark=44, the quarter of which is 11. 



The sum is as follows: 



11^X50 121X50^,2 feet inch 2 parts. 



144 144 



To find the true contents, the diameter of the tree in 

 the centre is found by callipers or tree compasses. For 

 the same size tree as before the figures will be 50 feet 

 long by 14 inches in diameter. The area of a circle 14 

 inches in diameter=142x0*7854=153'938 square inches. 



153-938x50 



144 



= 53 feet 5i inches. 



The figures for the square of J girth measurement — 

 viz., 42 feet — is 21 1 per cent, less than this figure. 



Another way to arrive at the true contents is to 

 multiply the square of I girth by the length and divide 



by 113= ^^1^=53 feet 6 inches. 113 is 21^ per cent. 



less than 144. 



To find the diameter of a tree when the girth is known, 



divide the latter figure by 3-f =2^2 • for instance, the above 



. ,, . . . 44x7 1 . 

 girth IS 44. -^^=14. 



In finding the area of a circle, instead of multiplying 

 by 0'7854, which makes a long sum, 0-8 may be used, and 



