218 On the Mensuration of Timber, 



the fourth column; thus *7071068, or IO00 ' oooo of thedt-g 



ameter Bb will be the calliper A a, when the tree is hewn, 

 to the inscribed square, or the most that it can be hewn 

 without waste. 



The second column shows the ratio or proportion, ex- 

 pressed in decimals, between the content of any tree mea- 

 sured in the round bv girting it, expressed by 1 or unity, 

 and the same tree hewn in any proportion, expressed by its 

 calliper in the first column, and then measured as square 

 timber by callipering it, or the ratio between the foot square 

 measure and the foot round measure, or between the loads 

 of the same denominations. The third column shows the 

 proportionate price that the same timber, measured by the 

 two methods, ought to bear (exclusive of the expense of 

 hewing, carriage/&c), expressed in shillings and decimals, 

 assuming the price of round timber to be 100 shillings (5l.) 

 for the convenience of calculating. In the fourth and last 

 column are mentioned the particular proportions of the num- 

 bers before mentioned against which they stand : thus the 

 ** side of the inscribed square" is also " l-4th of the peri- 

 meter;" and when the calliper A a is -8040316, the side A 

 or A is " l-5th of the perimeter," or sum of all the sides 

 A,B, A, b, a,b, a,B, or outline of the figure; also "de- 

 crease of l-5th in content" against • 70248 15, shows that in 

 this case the square measure of any tree is l-5th part less 

 than the round measure of that same tree ; at '7853982 they 

 are equal, and at -9619124 the square measure exceeds the 

 round measure by half ! In little more than in this last pro- 

 portion is the small timber generally hewn, which is used 

 by the barge-builders, carpenters, coopers and others in 

 London; and in the trade, the prices per load or foot of 

 round and hewn timber vary nearly in proportion thereto. 



The 



