Chap. IV.

ROMAN.

187

which crossed them immediately above the sill; besides these three perpendicular hangingposts were two others, let some inches into the side walls. These five posts were all onthe same face, and the spaces between them were all equal. When the balance beamturned upon its pivot, the three middle posts alone opened, and allowed the boats topass, after which the balance beam was turned back to its former position. At a littledistance was placed another balance beam, having attached to it a wide plank, to allow thelock keeper to pass over, as well as to place in the grooves of the hanging posts the smallplanks which served to exclude the water, by closing up the intervals ; these were on theside opposed to the current, and in number sufficient to keep the water at the requiredlevel. Such gates, or contrivances for damming up the waters of a river, were in use at avery early time in Italy , and two such were constructed at Governolo, in the twelfthcentury, to pen up the waters of the Mincio on the side of Mantua .

Zendrini, in his twelfth chapter, Delle Acque Correnti, has informed us of the changemade on this system in the year 1481, by the two brothers Dionisio and Pietro Domenico,of Viterbo; they were the first who used a lock chamber, inclosed by a double pair ofgates. So important an invention was made known and introduced throughout Europe ,and Leonardi da Vinci united the two canals of Milan by means of six such locks, havinga fall of seventeen braces; this was completed in the year 1497, as an inscription placedover the last sluice stated.

CATARACTAM IN EL1VO EXTRUCTUM UT PER IN-^QUALE SOLUM AD URBES COMMODITATEMCLTRO UTROQUE NAVES COMMKARENT. ANNO 1497.

All the other canals in Italy soon adopted them, and the whole system of inland navi-gation was greatly altered as well as benefited.

Zendrini’s account of the lock formed by the two brothers, Dionisio and Pietro Do-menico, clock-makers of Viterbo, is as follows:—“ In the year 1481, they obtained fromthe Signiori Contarini a certain site in the Bastia di Stra, a place well known near Padua ,to form in it a soratore of the Piovego, which was a canal from Padua to Stra; and in apetition made by these two brothers, of the same year, it is expressed that they will so act,that the boats will pass from the inclosure at Stra without any danger, managing it in sucha way that the water shall flow out with ease, and the boats shall neither be unloadednor required to be drawn; the conditions added are, that they shall form the ingegno,or execute the work, and also maintain it; this being granted with the revenue theydemand, in which is expressly comprised the lock of Stra. The aforesaid brothers beingrequired to form a buova , for the further perfection of the work.”

'Die State of Venice, according to Zendrini, has the honour of being the first to adoptthis invention; and this is all the information that can be obtained.

In the Milanese territory are several other canals, many for irrigation; near to Ollegiois a canal, which is fifteen miles in length, used for the purposes of navigation : it passesBuffolaro, Biagrasso, and Arsago to Milan. At Abiato is a branch eleven miles in length;its breadth at top is 130 feet, and at bottom forty-six ; this canal was made in the thirteenthcentury.

The great canal of Tesino and the branch from Pavia unite at Milan : the Muzza,which commences at Cassano, is in length forty miles, and has its other termination atCastiglione.

In Piedmont arc many considerable canals. The Naviglio d’ Ineais in length thirty-eightmiles; this unites the Doria Baltea with the Sessia: whilst another branch, thirteen milesin length, unites the Gardena river.

A canal passes from Dora Baltea, 27 miles in length, to the Po, which it joins four milesbelow Casal.

The Naviglio novo also falls into the Po, ten miles above Turin .

Along the Po, below the Milanese, the canal called Albinia falls into that river, ten milesabove Pavia. At Cremona the Naviglio della Communila unites the Lerico and the Oglio ,whilst other branches connect with the Po.

The Fossa di Puzzola is fifteen miles in length, unites the Mincio with the Tartaro : thecanal of St. George, 6 miles in length, connects the Lake of Mantua with the canal of Puz-zola ; and that of Martenaro, 8 miles in length, which passes to Borgo Fute, under the samelake with the Po. The Fossa Maestra is 5 miles in length, and joins Ozoma to the canalof Montanara. The Fossero, 7 miles in length, commences at the Mincio.

From Secchio to Panaro, by Modena, is a canal 16 miles in length, with several branchesfor the purposes of navigation and irrigation.

Fossa Rangone in the papal states is cut parallel to the Panaro, and two branches aremade from it, one to Po mort. From Mansolino is a canal 22 miles in length ; a portionof it is called Condotto di Conti. The Canal from Bologna to Ferrara is called di Naviglio,and terminates in the extensive marshes after a length of 24 miles. At Primaro, theCanal di Medicina falls into the Po. From the Great Po to the Po mort is the Canal