troducei. I he box has been extensively used in the oB 
portions oi the State, and has fulfilled a useful purpose. A| 
has the same fault as the Milanese module, added to the Bp 
that much less pains are usually taken in Colorado to 
after the details, and to secure the best arrangement possil 
to prevent the influence of other causes. yA 
As the term “oncia” was given to the Italian uni* 
the term inch has been used throughout this western colAS 
tor the corresponding unit. The statutes of Colorado prd 
scribe that water shall be measured through an orifice 
inches in height, with a pressure of water of 5 inches abovl 
the opening, and that the number of inches shall be the sam 
as the number of square inches in the orifice. But the terr 
I 5 n °t confined to the statute inch. On some ditches wate' 
is measured with a pressure of only two inches, on other 
without any, but the same term is used in all. 
A n A 1 J 1 M° nvenience w h> c h was soon discovered in the us 
ot the Milanese module was that the discharge was not i 
proportion to the nominal discharge. A person, for instanci 
who drew ioo oncia, receives more than ten times as much a 
one who drew i° oncia. The difference was so noticeabl 
that it was not long before the discharge from anyone orific 
was restricted to a certain number of oncia, generally si> 
1 he oncia varies from 34 to 47 litres per second, according a 
the orifice discharges one or six oncia. A similar variation i 
true of the statute inch of this State. The advantage in sue) 
methods is entirely in favor of those who draw the larg 
quantities. 1 he reason for this difference has been showi 
on pages 7 and 8.. 
There are other causes of variation, as in the distano 
the opening is above the bottom of the regulating box, in th< 
thickness of the sides, in the manner of its discharge; all o 
which render this module, excellent as its service has been ii 
the past, inaccurate and unreliable, and is leading to it' 
A module based on an entirely different principle wa: 
used on the Marseilles canal in France for a time, and wa: 
described in the earlier editions of this bulletin. This module 
consisted of a hollow vertical cylinder which was kept at £ 
constant distance below the surface of the water bv a float 
1 he water passed over the edge of the cylinder, and passer 
out through a channel which connected with the interior oi 
the cylinder. I he cylinder passed through a water tighr 
packing. In the previous editions attention was called to the 
probability that the module would be insensitive. On a per- 
