16 The Colorado Experimentation. 
tion which is permanent masonry, and divides the canal below the 
falls into two channels. At the upper end of this partition is 
a movable piece of wood coming to a point which is pivoted to 
the end of the partition, and can be held so that its upper end will 
include any assigned portion of the channel within certain limits. 
The length of the beak of wood is made so that it reaches to the 
upper drop when in line with the axis of the partition. The beak 
is set so as to include the desired portion of the channel and thus 
remains for twenty-four hours. 
A Masonry Regulator with Iron Gates, near Arles, in Southern Prance. 
At Lorca there is a system of sale something like that at Elche, 
for a portion of the area under cultivation, in which the amount 
which enters any ditch may vary from day to day. A divisor which 
may be called a needle divisor is used. The same care is used 
in the preparation of the channel as in the previous one described. 
A permanent masonry partition is placed in the channel. The pro¬ 
portion which enters the lateral channel is varied by varying the 
relative width of the main and lateral channels. This is done by 
inserting or taking out a series of narrow boards placed vertically. 
These are of uniform width." They are held in place both at top 
and bottom, and are carefully fitted to prevent leakage. The stream 
