198 
Italian Irrirjation. 
taken from tlie original blocks, for the use of which we are 
indebted to the courtesy of his representatives. 
Modulo SIagistkale of JIilax. 
I'lan. Fig. 1. 
M 
- o 
10 
lOFcct 
Longitudinal Section. I'Ig. I 
"The head A B, Fig. 1, is placed on the bank of the canal 
of supply with the sill C D, Fig. 2, on the same level as the 
bottom of this canal. It is formed of two side-walls or cheeks, 
of good masonry, in brick or stone, with a flooring generally of 
the latter material. To prevent erosive action, the bed of the 
canal, for such distance as the force of the current may render 
necessary, is paved with slabs of stone or boulders, both above 
and below the head. The outlet of the head is usually made of 
the same breadth as that of the measuring orifice G H, Fig. 2 ; 
Avliile its height is regulated by that of the head itself. The 
sluice-gate or j)aTatoJa, I K, Fig. 2, works in grooves, and is 
fitted with a rack and lever, by which it can be readily raised or 
depressed at pleasure. As the surface level of the canals of the 
Milanese varies comparatively little, the upriglit of the sluice 
has. a small catch in iron or wood attached to it, by which it is 
kept at a fixed height corresponding to the requisite pressure on 
the orifice G H, Fig. 2. 'J'his little catch is locally termed the 
(jatfello ; and as it is provided with a lock and key, the latter of 
which is intrusted to the guardian of the canal, the proprietor of 
the water-course is suj)p()sed to be restricted to his legitimate 
supply ; and j)robably is so, within reasonable limits, provided- 
always that the guardian is incorru])tible. 
" In rear of the sluice-gate at the head is placed the first 
chamber, L M, Figs. 1 and 2, called in the language of irriga- 
