8 
MEASUREMENT AND DIVISION OF WATER. 
truss across the ditch at the height of the division board 
and a depending cleat prevents more than a certain 
movement. In some cases at B C there is put a board, 
placed vertically, with the edge raised a few inches above 
the bottom of the channel. This then keeps the channel 
where the division is made of uniform depth, but it is of 
little benefit in equalizing the flow. 
The latter idea is in some places better developed. The 
water is brought to a state of approximate rest by a weir- 
board of some height—8 inches in one seen on the Farm¬ 
ers’ Union ditch, San Luis Valley—with a sharp crest on 
the up-stream side. The partition board extends length¬ 
wise of the ditch and has its upper end sharpened. As the 
water hills over the weir it flows away in the respective 
ditches. 
If water is brought to a complete state of rest, or ver} r 
nearly so, and if the water flows over the weir without 
lateral contraction, this method will give as satisfactory 
results as any divisors with which I am acquainted. 
An increase in the size of the ditch just at the division 
box will aid in bringing the water to rest. 
Boxes of this kind were used by, Hon. B. S. LaGrange 
near Greeley as early as 1871. 
Since the above was written Aymard’s “ Irrigation du 
Midi du l’Espagne ” has been received, in which he de¬ 
scribes a divisor used at Elche, based on the same principles. 
It is due to the Moors, and has been in use on this canal 
since their expulsion from Spain some hundreds of years 
ago. It differs from the one last described in having two 
drops instead of one, and in taking more pains with the 
canal of approach. For 150 or 200 feet above the divisor 
the canal has a very slight fall, in order that the water 
may have almost no velocity of approach. The canal is 
paved for about 10 feet above the divisor. There are two 
drops about three feet apart, the upper one of 10 inches, 
