Measurement and Division oe Water. 13 
pressed as “second feet,” and now the term, “Cusec,” a term orig¬ 
inating in India, is making way by its brevity. 
DIVISORS. 
A division into a definite fraction can rarely be exact, but 
frequently, the convenience of an approximate division more than 
counterbalances any inaccuracy there may be. If the water is 
to be divided into two equal portions, by placing the two lateral 
ditches in identical relations to the main ditch, in a straight and 
uniform channel, the division is exact. Emphasis should be paid 
upon the identical relation, for many divisions are seen where the 
conditions are not the same, as, e. g., one branch continues straight, 
the other may make an abrupt turn, one may pass through a covered 
box, etc. In these cases some advantage is given to the ditch having 
the freer discharge. The effect of these differences is greater than 
is generally supposed. It is, however, generally not difficult to 
meet these conditions if the parties desire. By repeating 
the process, the water may be subdivided into four, eight or 
sixteen parts. But where it is required to divide the water into 
two unequal, or into three or more portions, equal or not, the 
division becomes one of approximation only. The difficulty arises 
from the fact that the water has not uniform velocity across the 
whole channel. The center has greater velocity than that near the 
banks. If, therefore, equal openings be made across the channel, 
those near the center have the greater discharge. Making the cen¬ 
tral openings smaller only partially avoids the difficulty, for as 
the relative velocities of the center and sides differ with different 
quantities of water in the ditch, this arrangement would still be in¬ 
exact for any depth except that for which the adjustment is made. 
In its most common form the divisor consists of a partition 
dividing the channel into two portions. These portions are usually 
inexact in proportion to the respective claims. This, in effect, 
assumes that the velocity is uniform across the whole cross section, 
which is not the case, even in a uniform channel, and much less 
so in one irregular or in poor repair. Such a division is to the 
disadvantage of the smaller consumer. This is commonly the case 
in the divisors used in Colorado. 
The improvement in the ordinary methods of division is to 
make the velocity uniform across the channel. This is brought 
about in several ways. Sometimes by putting a board or drop 
at B-C, (fig. 1), making the division as the water drops over a 
weir; sometimes by increasing the width of the channel above B-C, 
so that there will be a still pool or reservoir, which will bring 
the water approximately to rest, and sometimes by a stilling-board, 
and sometime by making two or three such drops or falls. The 
purpose of all is the same, and that is to make the velocity of the 
