Italian Irrigation. 
181 
1512 feet disposable for the supply of 120 outlets on the main 
line. 
Some materials exist for enabling us to appi-oximnte to the loss 
of water caused bj filtration, evaporation, and waste in general on 
this line. Two very careful measurements have recently been 
made by adding together the separate discharges of each outlet 
from the main canal. According to the first measurement the 
total amount of these was 1612"5, and according to the second, 
1773 ; the mean being 161)2 cubic feet per second. Now, as 
the total discharge is 1851 cubic feet, the loss on the whole 
length of the canal is 158"25 cubic feet, or nearly 5 cubic feet 
per second for each mile. 
The area irrigated, exclusive of the branch canals, is 93,440 
acres in summer, or 61'8 acres for each cubic foot of discharge 
per second. In winter, 1750 are irrigated as marcite, or winter 
meadows. The price paid for water has varied extremely. In 
1376 a decree of Government fixed the water-rent per oncia at 
1 lira ; a decree of 1551 raised it to 36 lire ; twenty years later 
it had reached 125 lire. By a rapid and continuous advance, 
the rate had become, in the beginning of the eighteenth century, 
300 lire in the upper section, 400 in the centre, and 450 near 
Milan. 
The present rates are as follows : — 
£. s. d. 
Purchase in absolute property of 1 cubic foot per seconrl 291 10 0 
Annual rent of ditto in perpetuity, summer and winter 13 5 0 
Ditto ditto for summer only .. 12 10 0 
Annual rent taken from year to year, for summer .. 7 3 6 
Ditto ditto for winter.. .. 15 0 
Ditto ditto within Oj miles of 
Milan 1 12 0 
From the reckless manner in which grants have been made, 
the actual income is so small that it just covers the expenses. 
The revenue from all sources, navigation as well as irrigation, is 
no more than 1796Z., though the addition to the annual rental of 
the district may be very moderately estimated at 60,000/. per 
annum. 
VI. — The Cost of Constructing a Canal, and the Chief Works 
involved. 
No estimate is given of the cost of constructing the Naviglio 
Grande ; but in the case of the canal of Caluso, Colonel Baird 
Smith, being unable to obtain as accurate accounts of actual cost 
as he desired, formed an approximate calculation of the probable 
cost of the existing works at present prices. It is as follows : — 
