116 PRINCIPLES OF FEEDING FARM ANIMALS 



and most difficult step is to determine the content of 

 the stack in cubic feet, and the second step is to divide 

 the cubic feet in the stack by the number of cubic feet 

 in a ton. 



The United States Department of Agriculture ^ proposes 

 the following rule for estimating the number of cubic feet in 

 a stack : 



V = FOWL 

 where : 



r= volume in cubic feet. 



= distance in feet over the stack from the ground on one side 

 to the ground on the other side at a point directly opposite. 



IF = width in feet of the stack at the ground. 



L = length in feet of the stack at the ground. 



F^a, fraction varying from 0.25 to 0.37, depending upon the 

 shape of the stack. If the stack is low and nearly triangu- 

 lar, 0.25 should be used ; if it is tall, with verv^ full sides, 0.37 

 should be used. Any number in between these two may be 

 selected which seems to more nearly conform with the shape 

 of the stack. 



Of course, the accuracy of this method depends upon the 

 abihty of the operator to select the proper value for '' F." 

 Figure 23 shows cross sections of stacks of different shapes 

 and corresponding values of '' F." 



In Wyoming and Idaho, the following formula for finding 

 the cubic content of haystacks is legal : 



where : 



y = volume in cubic feet. 

 = distance over the stack in feet. 

 IF = width of the stack in feet. 

 L = length of the stack in feet. 



1 Cir. 131, Bureau of Plant Industry. 



