5 
governing the flow of water, the principles involved in distri¬ 
bution and measurement are the same here as there. We 
are finding the necessity of laws and regulations which they 
long ago found necessary. We shall find it necessary to take 
other steps which their experience long ago showed desirable. 
The Italian modules have been various, but until recently 
most of them have been based upon one idea—an erroneous 
one—which has been introduced into Colorado and the other 
western states in the form of the various miners’ inches. 
The need for measurement was felt before there was 
more than the most limited knowledge of hydraulic laws, and 
the methods of measurement date back, consequently, before 
the rise of hydraulic science. That they have been used for 
several centuries with even a fair degree of satisfaction re¬ 
flects great credit upon Soldati and the magistrates of Milan 
who so firmly grasped the conditions of the problem. That 
these measures are known to be incorrect is shown by the fact 
that all of the large modern canals have adopted other systems. 
The Cavour Canal, the Canale Casale, the Canale Villorsi 
have all adopted systems depending upon the weir. The in¬ 
sufficiency of the old measurement is evidenced by the fact 
that the Italian government required in one of its acts of 
concession granting water to a new canal, a plan for a new 
module for the measure and sale of water. That the old 
measures are still used, and will be used, is due to 
the fact that in time the individual users have acquired 
rights in the water which that particular method allows them, 
and any change which threatens those rights arouses at once 
intense opposition The same kind of conservatism is shown 
in Colorado, and the same varied customs are growing up. 
There are already numerous canals on which there are sev¬ 
eral different methods of measurement in use and where 
water is measured out differently to the early users. The 
changes affect the new users. 
The module proposed and adopted by this canal—the 
Canale Villoresi—will be especially described, because it 
seems to dispose of some of the difficulties which have made 
the weir objectionable. 
In the measurement of water there are two distinct 
classes of measuring boxes, different in their object. One is 
the dividing box, whose object is to give to each consumer 
some definite portion of the water flowing in the ditch. This 
box is found especially in the laterals owned in common by 
two or three neighbors, or in the smaller canals owned and 
operated by the stockholders. The other class is the meas- 
