8 The Colorado Experiment Station. 
staple in the lid support. The machine is now ready to start, the 
clutch is thrown in, and the box revolves upon the pipe. When 
three or four turns have been made, water is poured into the upright 
pipe until the desired amount has been added. By this time the 
concrete is thoroughly mixed. The clutch is loosened, the box stops 
revolving, the hoisting hook is hooked in the staple of the lid, the 
latch is loosened and the lid raised to the top of the lid support by 
means of the counter weight and rope. Now, by slightly setting the 
clutch, the contents of the mixer are dumped into the box beneath. 
The operator of the machine may now refill the mixer, while the 
other workmen take care of the mixed material. In this way a large 
amount of material may be run through the machine and perfect 
mixing is guaranteed. 
Many other systems of driving might have been used in place 
of the rope belt. The main gear of an old self-binder makes an ex¬ 
cellent gear for a mixer. An old mower gear may also be put to 
good use in this connection. 
It is not necessary to have the mixer driven by an engine or 
horse power. A crank may be attached and the machine turned by 
hand. Many prefer turning such a machine rather than mix the 
concrete with a shovel. 
poured POSTS. 
There are two general classes of mixtures which may be used 
in the construction of posts; the poured and. the tamped: In the 
poured mixture, enough water is used in mixing to make it thin 
enough to pour from a pail or scoop almost like water. The mix¬ 
ture is poured into a mold and allowed to remain in it until it has 
set, which is from one to five days, depending upon the time of year 
and the weather. In drying summer weather, from one to two 
days is usually sufficient. In cool or damp weather they must be 
left in the molds much longer. 
In order to make several posts of the poured type at once, it is 
necessary to have several molds ready for use. With 6 molds only 
6 posts could be made at once, and it would be necessary to wait 
until the cement was set before 6 more could be made. 
It was found that to make a good poured post, the mixture 
should be stirred or shaken immediately after placing in the mold; 
This should be done carefully to prevent displacement of reinforce¬ 
ment wires. This helps to remove the air from the mixture and 
makes a post of smooth finish. 
The experiment showed that a poured post of a certain mixture 
was stronger than a tamped post of the same mixture. It is enough 
stronger to justify anyone in constructing it in preference to the 
tamped one at the necessary additional expense for molds. The 
poured post is smoother, more nearly impervious to water, not so 
