NUMBER OF PLANTS. 181 



column wheels round and works back again, the flanking man 

 taking his direction from the last row of plants. 



The method is exceedingly simple, and yields a degree of 

 regularity sufficient for most purposes, provided the men are 

 well trained for the work. 



8. Xtuiiher of Plants. 



In the case of irregular planting the number of plants 

 required per acre can be roughly ascertained by dividing with 

 the square of the average planting distance, given in feet, into 

 43560 the number of square feet in an acre. 



For regular plantations the following calculations apply : — 

 Line planting : — 



Length of area ^ L 



Breadth ,, = B 



Distance between the rows . . . = d 

 ,, ,, plants in the rows . = d' ; 



then the number of rows = , + 1, 



and the number of plants in each row = — + 1, 



d 



hence the total number of plants: — 



N = (I; + l)x(B+l) = Ii4B + L+B . 



V d / \d' J d X d d d' 



Square plantin<j. — Here d = d' and 



d^ d 



TiiaiKjle planting. — Here the distance between the rows is 

 represented by the height of the equilateral triangle, which 

 is equal to d X sin 60° = d x -866 ; hence number of 



rows = ~ -—- + 1, and number of plants in each row, 



d X -866 '■ 



T_) "O p 



either alternately = y + 1 and — ; or always according as 



B 



to wliether — is a whole number, or ^ more. 



