_The Canals of Venice._—In speaking of the canals of Italy, it would be unpardonable to omit due reference to those which give to Venice, the “mistress of the Adriatic,” her peculiar and pre-eminent position. Founded in the year 452, soon after Attila invaded Italy, Venice is built upon a number of small islands, and is divided into two nearly equal parts by the “Grand Canal,” 1200 yards in length, and 100 feet in breadth. Many smaller canals branch off from the Grand Canal. These are crossed by some five hundred bridges, many of them of considerable architectural pretensions. The construction of the canals of Venice was a work that would be naturally unlike that of laying out a canal in the ordinary course. The whole city, built on a number of small islands, is more or less constructed on piles; there is an almost dead level throughout; and the waterways would, no doubt, in the majority of cases, be naturally formed, at least to a partial extent. There is, however, very little information extant as to the circumstances under which the work of adapting the canals to the requirements of the population was carried out. _Irrigation Canals._—It would hardly be proper to pass from the canal system of Italy without making some remarks on the excellent system of irrigation canals that has been provided in Lombardy and Piedmont. Navigation canals take priority over irrigation canals in Lombardy in point of origin, but not to a great extent. The Vettabbia Canal, which is supposed to have been used for navigation previous to the eleventh century, is claimed as the oldest existing canal in Lombardy. In the latter part of the twelfth century, the Cistercian monks of Chiaravalle obtained possession of this canal, and applied its waters to irrigation purposes. Not very long afterwards the same order of monks constructed the Ticinello, a canal derived from the Ticino at Tornavento, and it was used exclusively for irrigation until 1177, when it was enlarged and partly opened for navigation. In 1257, the same canal was so far enlarged as to connect Milan with Lake Maggiore, and the waterway is now known as the Naviglio Grande.