8 The Colorado Experiment Station 
Reinforcement .—Cement and concrete work has the prop¬ 
erty of resisting great, crushing stresses, but when subjected 
to tensile stress the best of it breaks very easily. For this reason 
it becomes necessary to put some material possessing great tensile 
strength into the post, in order that the full crushing strength of 
the cement or concrete may be utilized. Iron is the most satis¬ 
factory material from which to make reinforcement. The rein¬ 
forcement should be placed in the post as near the corner as pos¬ 
sible. This places it as far as possible from the neutral axis thus 
giving it the greatest advantage in strengthening the post. In 
order that the reinforcements may be properly held and protected 
by the cement, it is a good plan to place it from Y to inch in 
from each side. 
The material used for reinforcement should be strong, light 
and rough enough to permit the mixture to get a firm grip upon it. 
It should be very rigid, with little or no tendency to spring or 
stretch. The experiments showed that ordinary iron or steel wire 
was cheapest, strongest and easiest to procure. In order to provide 
a means by which the cement may cling firmly to the wire, it is 
best to twist two small wires together instead of using one large 
one. 
Caring the Posts .—In order for the cement to become 
thoroughly cured or “set” water must be supplied to aid in the 
action. For the first thirty days the posts should be kept wet if 
the best results are to be expected. 
The most favorable conditions for conserving the moisture 
consists in curing the posts in a shed where the wind does not 
strike them. Under these conditions neither the sun’s rays nor 
the wind have a chance to dry out the posts too rapidly. The posts 
should be thoroughly sprinkled every day for at least thirty days. 
Wire Fasteners .—An inventor has devised a cast-iron socket 
which is placed in the post. Later the wire is fastened to 
the post by driving a staple into the socket or staple holder. The 
staples pull out easily and the sockets add greatly to the cost of 
the post. 
Another system consists of two staples which have the prongs 
bent to the side. The staples are placed about one-quarter inch 
apart, with the prongs projecting to the side. The line wire is 
placed between the two staples and a nail or a piece of wire is 
driven down through the staples, outside of the line wire. As the 
tips of the staple touch the reinforcement wires, direct electric con¬ 
nections are established between the line wire and the ground at 
the bottom of the post. This, it is claimed by the patentee, insures 
the user against loss of stock by lightning. The system is called 
the “Double Staple.” (See Fig. 2.) 
