6 
MEASUREMENT AND DIVISION OF WATER. 
vide the water. A module may evidently serve as a divisor, 
for if the amount to be divided is known it is a simple 
mattter to determine the quantity to which each is en¬ 
titled and to regulate the module accordingly. There will 
always be cases where divisors will be by all means the 
most convenient, but these cases will be mostly in the 
small ditches from which few take water. In all other 
cases modules of one kind or another will be found the 
better. 
DIVISORS. 
As ordinarily constructed, the division can rarely be 
exact, but frequently the convenience of an approximate 
division more than counterbalances any inaccuracy there 
may be. The larger ditches rarely have occasion to use 
divisors, for, even if the ditch has to pro rate the water, a 
better distribution can be effected by means of modules. 
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 laid on the identical relation, 
for many divisions are seen where the conditions are not 
the same, as, c. g ., one man’s ditch may continue straight, 
the other may make an abrupt turn, one may pass , 
through a covered box, etc. In these cases some advantage 
will be given to the party having the freer discharge. The 
effect of these differences is greater than is generally sup¬ 
posed. It is, however, generally easy to fill these condi¬ 
tions if the parties desire. In the same way the water 
may be subdivided into four, eight or sixteen equal parts. 
But where it is required to divide the water into two un¬ 
equal, or into three or more portions, equal or not, the di¬ 
vision becomes one of approximation only. The difficulty 
arises from the fact that the water has not uniform velocity ; 
that near the center has greater velocity than that near the 
banks. If, therefore, equal openings be made across the 
