Measurement and Division oe Water. 21 
ognized in the sixteenth century and was adopted in 1585. How¬ 
ever, the interference this was supposed to cause with vested rights 
led to great trouble and to the condemnation at that time of 
Soldati, who proposed and urged it, though it is now recognized 
as having been essentially just.* 
Experience showed that the discharge of the Milanese module 
was not in proportion to the nominal discharge. A person, for 
example, who drew one hundred oncia received more than ten 
times as much as the one who drew ten. It was, therefore, soon 
provided, that the discharge through any one orifice should not 
exceed a given number of oncia, generally six. The oncia varies 
from 34 to 47 liters per second, according as the orifice discharge 
from one to six oncia. A similar variation is true of the statute 
inch in this state. The advantage is entirely in favor of those 
who draw the large quantities. 
There are other causes of variation, as in the distance the 
opening is above the bottom of the box, in the thickness of the 
sides, in the manner of its discharge. All of these render this 
module inaccurate and unreliable and is leading to its aban¬ 
donment. 
A module based on an entirely different principle was used 
on the Marseilles Canal in France and described in the earlier 
editions of this bulletin. This module consisted of a hollow vertical 
cylinder kept at a constant distance below the surface of the water 
by a float. The cylinder passed through a water-tight packing. 
It was noted in Bulletin 13 that this module would probably be 
insensitive. On a personal visit to the Marseilles Canal, it 
was learned that it had been abandoned for that reason. A modi¬ 
fied form was attempted in Australia, where the connection was 
made by a bellows arrangement of leather. These and many other 
devices have been proposed, but do not seem to be especially valu¬ 
able. It has been proposed to use a form of Venturi meter, a device 
invented by Clemens Herschel. The present objection is to the 
cost. A modified form of this has been proposed by Mr. R. G. 
Kennedy, of India, in an attempt to meet conditions given to him 
by the writer. 
Other ways of modifying the size of the opening have 
been tried. In one, the water passed through a hole in which 
was a plug of metal, which was lifted by a float. The hole was 
circular. The diameter of the plug varies at different points, so 
that the size of the opening reduced as the head increased. In 
this case there is little or no friction. It is mentioned as an illus- 
*The history of this event and the trouble arising therefrom is 
given in Bruschetti’s Storia del Irrigazione del Milanesi, in his complete 
works, Vol. 2, pages 118 to 135. It is condensed in Buffon’s des Canaux 
d’ Irrigation d’ Italie Septentrionale. 
