484 Artificial Irrigation. [ Oct., 
and extended. In France it is still extensively employed, more 
especially in the southern districts. In Eastern Spain the old 
Arab systems of irrigation are to be met with to this day; and 
it appears that the Spanish conquerors, far less civilized than their 
defeated foes, could, at the best, merely follow in the footsteps of 
the Arabs; but the enlightened subjects of the Western Caliphs 
had brought the science of irrigation, and indeed of all branches 
of agriculture, to the highest perfection, Markham, in his work 
above referred to, states—“Thus the irrigation systems of the 
Arabs continued in operation, with slight alterations and few im- 
provements, after the Spanish conquest; the old rules and customs 
were adopted by the Spanish municipalities, and many of them have 
since been embodied in modern ordinances; and the works of irri- 
gation have simply been kept in working order, and periodically 
cleaned, according to immemorial usage. The Arabs irrigated 
every place to which water could be conveyed, either by sub- 
terranean tunnels or ordinary canals; and most of these localities 
continue to present bright patches of green amidst the bare and 
rocky hills.” 
The repeated irruptions of the barbarian hordes of the north 
into the valley of the Po during the earlier centuries of the 
Christian era, led naturally to the neglect of even those works 
of irrigation which in happier times may have been constructed, 
and the rich plain of Lombardy was threatened with devastation. 
“A great part of the province,’ Bruschetti remarks, “ was at this 
time covered with forests. Tracts, now richly cultivated, were then 
stagnant marshes or arid wastes. The cultivation of rice or the 
mulberry was unknown, and the products of the soil were the 
common grains required for food, and flax for clothing.” The 
struggle against the superabundant waters, which threatened to 
submerge the plain, did not, however, begin for two centuries later. 
Before the year 1100, but at what precise date is unknown, the 
ancient works in the interior of Milan, originally constructed in 
the times of the Romans, were restored and extended. The 
destruction of Milan by the Emperor Frederick Barbarossa in 
1162, and its subsequent re-construction on a grander scale 
about 1176, led to a great extension of these hydraulic works. 
Up to the middle of the twelfth century there appears no reference 
to the employment of the waters contained in these canals for irri- 
gation. Continued local traditions, however, established the fact, 
that during the latter half of this century the modern system of 
irrigation had its origin; and it was to the intelligence of the 
Monks of St. Bernard, who founded the monastery of Chiaravyalle, 
near Milan, that Lombardy was indebted for this blessing. 
The date of the most ancient of the existing canals of Piedmont 
ascends to the commencement of the fourteenth century—the same 
