226 ENGINEERING ON THE FARM 



are: the extent of land used, as the roots extend out 

 8 to 10 feet on either side and take the fertility and mois- 

 ture out of the soil; and the degree of attention required 

 each year to keep it in shape. However, if proper attention 

 is given to it, there is no replacement cost or labor. The 

 trimming can be done when other work is not pressing. It is 

 questionable whether a hedge fence is any more expensive 

 in a long number of years than any other class of fence. 



Board fence. Formerly barnyard and field fences in 

 prairie country were frequently made of sawed lumber. 

 Boards 6 inches wide, i inch thick, and 1 2 to 16 feet long were 

 nailed to posts set 6 to 8 feet apart. Board fences are fairly 

 satisfactory for a time, but they are short-lived because the 

 lumber decays and the stock rubbing against them break 

 them down. This use of 1" X 6" boards gave them the 

 nickname fencing. 



Wire fences. The development of fencing material by 

 means of smooth wires twisted and with short barbs 

 inserted every 4 to 6 inches marks the beginning of wire- 

 fence construction and has resulted in nearly all of our 

 modern fences being some combination of wire. 



A metal from which wire can be made must be ductile 

 and be tenacious after the wire is formed. The wire is 

 produced from a slender bar or rod of metal drawn through 

 a die. After drawing, the wire is usually hard and brittle 

 and it is necessary to soften it by annealing for further draw- 

 ing. It is drawn by a machine which holds the dies and 

 supplies the power. The single-block machine draws a 

 wire of but one diameter, while in a continuous machine 

 the wire passes from one block to another, the final diameter 

 being produced at one passage through the machine. 



POSTS 



As posts are the parts of a fence that are most likely to 

 decay first, attention should be given to their selection. 

 Fence posts are of three kinds: wood, concrete, and metal. 



